Adding solution

Added solution for last few weeks

DataBases/PythonORM/advanced_django_model_techniques_exercise/caller.py

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+import os
+from decimal import Decimal
+
+import django
+from django.core.exceptions import ValidationError
+
+# Set up Django
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "orm_skeleton.settings")
+django.setup()
+
+# Import your models here
+from main_app.models import Customer, Book, Product, DiscountedProduct, SpiderHero, FlashHero, Document
+
+# Create queries within functions
+
+if __name__ == '__main__':
+    pass
+    from django.contrib.postgres.search import SearchVector
+
+    # Create the first 'Document' object with a title and content.
+    document1 = Document.objects.create(
+        title="Django Framework 1",
+        content="Django is a high-level Python web framework for building web applications.",
+    )
+
+    # Create the second 'Document' object with a title and content.
+    document2 = Document.objects.create(
+        title="Django Framework 2",
+        content="Django framework provides tools for creating web pages, handling URL routing, and more.",
+    )
+
+    # Update the 'search_vector' field in the 'Document' model with search vectors.
+    Document.objects.update(search_vector=SearchVector('title', 'content'))
+
+    # Perform a full-text search for documents containing the words 'django' and 'web framework'.
+    results = Document.objects.filter(search_vector='django web framework')
+
+    # Print the search results.
+    for result in results:
+        print(f"Title: {result.title}")

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/admin.py

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+from django.contrib import admin
+
+# Register your models here.

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/apps.py

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+from django.apps import AppConfig
+
+
+class MainAppConfig(AppConfig):
+    default_auto_field = 'django.db.models.BigAutoField'
+    name = 'main_app'

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/migrations/0001_initial.py

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+# Generated by Django 5.0.4 on 2024-07-20 09:48
+
+import django.core.validators
+import main_app.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Customer',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100, validators=[main_app.validators.ValidName()])),
+                ('age', models.PositiveIntegerField(validators=[django.core.validators.MinValueValidator(18, 'Age must be greater than or equal to 18')])),
+                ('email', models.EmailField(error_messages={'invalid': 'Enter a valid email address'}, max_length=254)),
+                ('phone_number', models.CharField(max_length=13, validators=[main_app.validators.CountryPhoneNumberValidator()])),
+                ('website_url', models.URLField(error_messages={'invalid': 'Enter a valid URL'})),
+            ],
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/migrations/0002_book_movie_music.py

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+# Generated by Django 5.0.4 on 2024-07-20 10:16
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Book',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=100)),
+                ('description', models.TextField()),
+                ('genre', models.CharField(max_length=100)),
+                ('created_at', models.DateTimeField(auto_now=True)),
+                ('author', models.CharField(max_length=100, validators=[django.core.validators.MinLengthValidator(5, 'Author must be at least 5 characters long')])),
+                ('isbn', models.CharField(max_length=20, unique=True, validators=[django.core.validators.MinLengthValidator(6, 'ISBN must be at least 6 characters long')])),
+            ],
+            options={
+                'ordering': ['-created_at', 'title'],
+                'abstract': False,
+            },
+        ),
+        migrations.CreateModel(
+            name='Movie',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=100)),
+                ('description', models.TextField()),
+                ('genre', models.CharField(max_length=100)),
+                ('created_at', models.DateTimeField(auto_now=True)),
+                ('director', models.CharField(max_length=100, validators=[django.core.validators.MinLengthValidator(8, 'Director must be at least 8 characters long')])),
+            ],
+            options={
+                'verbose_name': 'Model Movie',
+                'verbose_name_plural': 'Models of type -Movie',
+                'ordering': ['-created_at', 'title'],
+                'abstract': False,
+            },
+        ),
+        migrations.CreateModel(
+            name='Music',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=100)),
+                ('description', models.TextField()),
+                ('genre', models.CharField(max_length=100)),
+                ('created_at', models.DateTimeField(auto_now=True)),
+                ('artist', models.CharField(max_length=100, validators=[django.core.validators.MinLengthValidator(9, 'Artist must be at least 9 characters long')])),
+            ],
+            options={
+                'verbose_name': 'Model Music',
+                'verbose_name_plural': 'Models of type - Music',
+                'ordering': ['-created_at', 'title'],
+                'abstract': False,
+            },
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/migrations/0003_alter_movie_options.py

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+# Generated by Django 5.0.4 on 2024-07-20 10:19
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0002_book_movie_music'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='movie',
+            options={'ordering': ['-created_at', 'title'], 'verbose_name': 'Model Movie', 'verbose_name_plural': 'Models of type - Movie'},
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/migrations/0004_alter_book_options.py

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+# Generated by Django 5.0.4 on 2024-07-20 10:21
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0003_alter_movie_options'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='book',
+            options={'ordering': ['-created_at', 'title'], 'verbose_name': 'Model Book', 'verbose_name_plural': 'Models of type - Book'},
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/migrations/0005_product_discountedproduct.py

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+# Generated by Django 5.0.4 on 2024-07-20 10:38
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0004_alter_book_options'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Product',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('price', models.DecimalField(decimal_places=2, max_digits=10)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='DiscountedProduct',
+            fields=[
+            ],
+            options={
+                'proxy': True,
+                'indexes': [],
+                'constraints': [],
+            },
+            bases=('main_app.product',),
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/migrations/0006_hero_flashhero_spiderhero.py

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+# Generated by Django 5.0.4 on 2024-07-20 12:44
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0005_product_discountedproduct'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Hero',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('hero_title', models.CharField(max_length=100)),
+            ],
+            options={
+                'abstract': False,
+            },
+        ),
+        migrations.CreateModel(
+            name='FlashHero',
+            fields=[
+            ],
+            options={
+                'proxy': True,
+                'indexes': [],
+                'constraints': [],
+            },
+            bases=('main_app.hero',),
+        ),
+        migrations.CreateModel(
+            name='SpiderHero',
+            fields=[
+            ],
+            options={
+                'proxy': True,
+                'indexes': [],
+                'constraints': [],
+            },
+            bases=('main_app.hero',),
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/migrations/0007_document.py

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+# Generated by Django 5.0.4 on 2024-07-20 12:55
+
+import django.contrib.postgres.search
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0006_hero_flashhero_spiderhero'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Document',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=200)),
+                ('content', models.TextField()),
+                ('search_vector', django.contrib.postgres.search.SearchVectorField(null=True)),
+            ],
+            options={
+                'indexes': [models.Index(fields=['search_vector'], name='main_app_do_search__c97410_idx')],
+            },
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/mixins.py

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+from django.db import models
+
+
+class RechargeEnergyMixin(models.Model):
+    def recharge_energy(self, amount: int):
+        # print(self.energy, amount)
+        self.energy += amount
+
+    class Meta:
+        abstract = True

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/models.py

@@ -0,0 +1,157 @@
+from decimal import Decimal
+
+from django.contrib.postgres.search import SearchVectorField
+from django.core.validators import MinValueValidator, EmailValidator, URLValidator, MinLengthValidator
+from django.db import models
+
+from main_app.mixins import RechargeEnergyMixin
+from main_app.validators import ValidName, CountryPhoneNumberValidator
+
+
+# Create your models here.
+
+class Customer(models.Model):
+
+    name = models.CharField(max_length=100, validators = [ValidName()])
+    age = models.PositiveIntegerField(validators = [MinValueValidator(18,"Age must be greater than or equal to 18")])
+    email = models.EmailField(error_messages={'invalid': 'Enter a valid email address'})
+    phone_number = models.CharField(max_length=13, validators=[CountryPhoneNumberValidator()])
+    website_url = models.URLField(error_messages={'invalid':"Enter a valid URL"})
+
+
+class BaseMedia(models.Model):
+
+    class Meta:
+        abstract = True
+        ordering = ['-created_at','title']
+
+    title = models.CharField(max_length=100)
+    description = models.TextField()
+    genre = models.CharField(max_length=100)
+    created_at = models.DateTimeField(auto_now=True)
+
+class Book(BaseMedia):
+    author = models.CharField(max_length=100, validators=[MinLengthValidator(5,"Author must be at least 5 characters long")])
+    isbn = models.CharField(max_length=20, unique=True, validators=[MinLengthValidator(6,  "ISBN must be at least 6 characters long")])
+
+    class Meta(BaseMedia.Meta):
+        verbose_name = 'Model Book'
+        verbose_name_plural = 'Models of type - Book'
+
+
+class Movie(BaseMedia):
+    director = models.CharField(max_length=100, validators=[MinLengthValidator(8, "Director must be at least 8 characters long")])
+
+    class Meta(BaseMedia.Meta):
+        verbose_name = 'Model Movie'
+        verbose_name_plural = 'Models of type - Movie'
+
+
+class Music(BaseMedia):
+    artist = models.CharField(max_length=100, validators=[MinLengthValidator(9, "Artist must be at least 9 characters long")])
+
+    class Meta(BaseMedia.Meta):
+        verbose_name = 'Model Music'
+        verbose_name_plural = 'Models of type - Music'
+
+
+class Product(models.Model):
+    name = models.CharField(max_length=100)
+    price = models.DecimalField(max_digits=10, decimal_places=2)
+
+    def calculate_tax(self):
+        return self.price * Decimal(0.08)
+
+    def calculate_shipping_cost(self, weight: Decimal):
+        return weight * Decimal(2.00)
+
+    def format_product_name(self):
+        return f"Product: {self.name}"
+
+
+
+class DiscountedProduct(Product):
+
+    class Meta:
+        proxy = True
+
+    def calculate_price_without_discount(self):
+        return self.price * Decimal(1.20)
+
+    def calculate_tax(self):
+        return self.price * Decimal(0.05)
+
+    def calculate_shipping_cost(self, weight: Decimal):
+        return weight * Decimal(1.50)
+
+    def format_product_name(self):
+        return f'Discounted Product: {self.name}'
+
+
+class Hero(RechargeEnergyMixin):
+    name = models.CharField(max_length=100)
+    hero_title = models.CharField(max_length=100)
+    energy = models.PositiveIntegerField()
+
+    @property
+    def energy(self):
+        return self.__energy
+
+    @energy.setter
+    def energy(self, value):
+        try:
+            energy = self.__energy
+            energy = value
+            if energy < 0:
+                raise ValueError('cannot decrease below zero')
+            self.__energy = energy
+        except AttributeError:
+            self.__energy = value
+        self.__energy = min(100, self.__energy)
+
+
+class SpiderHero(Hero):
+
+    def swing_from_buildings(self):
+        try:
+            self.energy -= 80
+        except ValueError:
+            return f"{self.name} as Spider Hero is out of web shooter fluid"
+        self.energy = max(1,self.energy)
+        self.clean()
+        self.save()
+        return f"{self.name} as Spider Hero swings from buildings using web shooters"
+
+    class Meta:
+        proxy = True
+
+
+class FlashHero(Hero):
+
+    def run_at_super_speed(self):
+        try:
+            self.energy -= 65
+        except ValueError:
+            return f"{self.name} as Flash Hero needs to recharge the speed force"
+        self.energy = max(1, self.energy)
+        self.clean()
+        self.save()
+        return f"{self.name} as Flash Hero runs at lightning speed, saving the day"
+
+    class Meta:
+        proxy=True
+
+
+class Document(models.Model):
+    title = models.CharField(max_length=200)
+    content = models.TextField()
+    search_vector = SearchVectorField(null=True)
+
+    class Meta:
+        indexes = [
+            models.Index(fields=['search_vector'])
+        ]
+
+
+
+

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/tests.py

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+from django.test import TestCase
+
+# Create your tests here.

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/validators.py

@@ -0,0 +1,32 @@
+from re import match
+
+from django.core.exceptions import ValidationError
+# from django.db import models
+from django.core.validators import BaseValidator
+
+class ValidName(BaseValidator):
+
+    def __init__(self, *args, **kwargs):
+        self.message = kwargs.get('message', "Name can only contain letters and spaces")
+        super().__init__(None, **kwargs)
+
+    def __call__(self, value):
+        if not isinstance(value, str) or not value.replace(' ','').isalpha():
+            raise ValidationError(self.message)
+
+
+class CountryPhoneNumberValidator(BaseValidator):
+
+    def __init__(self, *args, **kwargs):
+        self.phone_code = kwargs.get('country_code','+359')
+        try:
+            del kwargs['country_code']
+        except:
+            pass
+        self.message = kwargs.get('message',f"Phone number must start with '{self.phone_code}' followed by 9 digits")
+        super().__init__(None,**kwargs)
+
+    def __call__(self, value):
+        pattern = fr'^\{self.phone_code}\d{{9}}$'
+        if not match(pattern, value):
+            raise ValidationError(self.message)

DataBases/PythonORM/advanced_django_model_techniques_exercise/main_app/views.py

@@ -0,0 +1,3 @@
+from django.shortcuts import render
+
+# Create your views here.

DataBases/PythonORM/advanced_django_model_techniques_exercise/manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()

DataBases/PythonORM/advanced_django_model_techniques_exercise/orm_skeleton/asgi.py

@@ -0,0 +1,16 @@
+"""
+ASGI config for orm_skeleton project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_asgi_application()

DataBases/PythonORM/advanced_django_model_techniques_exercise/orm_skeleton/settings.py

@@ -0,0 +1,135 @@
+"""
+Django settings for orm_skeleton project.
+
+Generated by 'django-admin startproject' using Django 4.2.4.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/4.2/ref/settings/
+"""
+
+from pathlib import Path
+
+# Build paths inside the project like this: BASE_DIR / 'subdir'.
+BASE_DIR = Path(__file__).resolve().parent.parent
+
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/4.2/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'django-insecure-cd%2g!p_@ut(kc8)%bd9_*@)i@kff^orkvy=!c#i!l+ak98)%0'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+
+# Application definition
+
+INSTALLED_APPS = [
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+    'main_app',
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+]
+
+ROOT_URLCONF = 'orm_skeleton.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [BASE_DIR / 'templates']
+        ,
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = 'orm_skeleton.wsgi.application'
+
+
+# Database
+# https://docs.djangoproject.com/en/4.2/ref/settings/#databases
+
+# DATABASES = {
+#     'default': {
+#         'ENGINE': 'django.db.backends.sqlite3',
+#         'NAME': BASE_DIR / 'db.sqlite3',
+#     }
+# }
+
+DATABASES = {
+    "default": {
+        "ENGINE": "django.db.backends.postgresql",
+        "NAME": "advanced_django_model_techniques_exercise",
+        "USER": "postgres-user",
+        "PASSWORD": "password",
+        "HOST": "localhost",
+        "PORT": "5432",
+    }
+}
+
+# Password validation
+# https://docs.djangoproject.com/en/4.2/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+
+# Internationalization
+# https://docs.djangoproject.com/en/4.2/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_TZ = True
+
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/4.2/howto/static-files/
+
+STATIC_URL = 'static/'
+
+# Default primary key field type
+# https://docs.djangoproject.com/en/4.2/ref/settings/#default-auto-field
+
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

DataBases/PythonORM/advanced_django_model_techniques_exercise/orm_skeleton/urls.py

@@ -0,0 +1,22 @@
+"""
+URL configuration for orm_skeleton project.
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/4.2/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  path('', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.urls import include, path
+    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
+"""
+from django.contrib import admin
+from django.urls import path
+
+urlpatterns = [
+    path('admin/', admin.site.urls),
+]

DataBases/PythonORM/advanced_django_model_techniques_exercise/orm_skeleton/wsgi.py

@@ -0,0 +1,16 @@
+"""
+WSGI config for orm_skeleton project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_wsgi_application()

DataBases/PythonORM/advanced_django_model_techniques_lab/caller.py

@@ -0,0 +1,42 @@
+import os
+import django
+from django.core.exceptions import ValidationError
+
+
+# Set up Django
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "orm_skeleton.settings")
+django.setup()
+
+# Import your models here
+from main_app.models import Restaurant
+
+# Create queries within functions
+
+if __name__ == '__main__':
+    pass
+    from main_app.models import Restaurant, RegularRestaurantReview, FoodCriticRestaurantReview
+    from django.core.exceptions import ValidationError
+
+    restaurant1 = Restaurant.objects.create(name="Restaurant A", location="123 Main St.",
+                                            description="A cozy restaurant", rating=4.88)
+    RegularRestaurantReview.objects.create(reviewer_name="Bob", restaurant=restaurant1,
+                                           review_content="Good experience overall.", rating=4)
+    RegularRestaurantReview.objects.create(reviewer_name="Aleks", restaurant=restaurant1,
+                                           review_content="Great food and service!", rating=5)
+
+    duplicate_review = RegularRestaurantReview(reviewer_name="Aleks", restaurant=restaurant1,
+                                               review_content="Another great meal!", rating=5)
+
+    try:
+        duplicate_review.full_clean()
+        duplicate_review.save()
+    except ValidationError as e:
+        print(f"Validation Error: {e}")
+
+    print("Regular Restaurant Review:")
+    print(f"Model Name: {RegularRestaurantReview._meta.verbose_name}")
+    print(f"Model Plural Name: {RegularRestaurantReview._meta.verbose_name_plural}")
+
+    print("Food Critic Restaurant Review:")
+    print(f"Model Name: {FoodCriticRestaurantReview._meta.verbose_name}")
+    print(f"Model Plural Name: {FoodCriticRestaurantReview._meta.verbose_name_plural}")

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/admin.py

@@ -0,0 +1,3 @@
+from django.contrib import admin
+
+# Register your models here.

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+
+class MainAppConfig(AppConfig):
+    default_auto_field = 'django.db.models.BigAutoField'
+    name = 'main_app'

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/migrations/0001_initial.py

@@ -0,0 +1,25 @@
+# Generated by Django 5.0.4 on 2024-07-18 13:25
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Restaurant',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100, validators=[django.core.validators.MinLengthValidator(2, 'Name must be at least 2 characters long.'), django.core.validators.MaxLengthValidator(100, 'Name cannot exceed 100 characters.')])),
+                ('location', models.CharField(max_length=200, validators=[django.core.validators.MinLengthValidator(2, 'Location must be at least 2 characters long.'), django.core.validators.MaxLengthValidator(200, 'Location cannot exceed 200 characters.')])),
+                ('description', models.TextField(blank=True, null=True)),
+                ('rating', models.DecimalField(decimal_places=2, max_digits=3, validators=[django.core.validators.MinValueValidator(0.0, 'Rating must be at least 0.00.'), django.core.validators.MaxValueValidator(5.0, 'Rating cannot exceed 5.00.')])),
+            ],
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/migrations/0002_menu.py

@@ -0,0 +1,24 @@
+# Generated by Django 5.0.4 on 2024-07-19 12:08
+
+import django.db.models.deletion
+import main_app.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Menu',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('description', models.TextField(validators=[main_app.validators.validate_menu_categories(limit_value=['Appetizers', 'Main Course', 'Desserts'], message='The menu must include each of the categories "Appetizers", "Main Course", "Desserts".')])),
+                ('restaurant', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.restaurant')),
+            ],
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/migrations/0003_restaurantreview.py

@@ -0,0 +1,25 @@
+# Generated by Django 5.0.4 on 2024-07-19 12:25
+
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0002_menu'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='RestaurantReview',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('reviewer_name', models.CharField(max_length=100)),
+                ('review_content', models.TextField(validators=[django.core.validators.MaxValueValidator(5)])),
+                ('rating', models.PositiveIntegerField()),
+                ('restaurant', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.restaurant')),
+            ],
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/migrations/0004_alter_restaurantreview_rating_and_more.py

@@ -0,0 +1,24 @@
+# Generated by Django 5.0.4 on 2024-07-19 12:26
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0003_restaurantreview'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='restaurantreview',
+            name='rating',
+            field=models.PositiveIntegerField(validators=[django.core.validators.MaxValueValidator(5)]),
+        ),
+        migrations.AlterField(
+            model_name='restaurantreview',
+            name='review_content',
+            field=models.TextField(),
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/migrations/0005_alter_restaurantreview_options_and_more.py

@@ -0,0 +1,21 @@
+# Generated by Django 5.0.4 on 2024-07-19 12:28
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0004_alter_restaurantreview_rating_and_more'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='restaurantreview',
+            options={'ordering': ['-rating'], 'verbose_name': 'Restaurant Review', 'verbose_name_plural': 'Restaurant Reviews'},
+        ),
+        migrations.AlterUniqueTogether(
+            name='restaurantreview',
+            unique_together={('reviewer_name', 'restaurant')},
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/migrations/0006_foodcriticrestaurantreview_regularrestaurantreview_and_more.py

@@ -0,0 +1,53 @@
+# Generated by Django 5.0.4 on 2024-07-19 12:41
+
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0005_alter_restaurantreview_options_and_more'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='FoodCriticRestaurantReview',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('reviewer_name', models.CharField(max_length=100)),
+                ('review_content', models.TextField()),
+                ('rating', models.PositiveIntegerField(validators=[django.core.validators.MaxValueValidator(5)])),
+                ('food_critic_cuisine_area', models.CharField(max_length=100)),
+                ('restaurant', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.restaurant')),
+            ],
+            options={
+                'verbose_name': 'Food Critic Review',
+                'verbose_name_plural': 'Food Critic Reviews',
+                'ordering': ['-rating'],
+                'abstract': False,
+                'unique_together': {('reviewer_name', 'restaurant')},
+            },
+        ),
+        migrations.CreateModel(
+            name='RegularRestaurantReview',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('reviewer_name', models.CharField(max_length=100)),
+                ('review_content', models.TextField()),
+                ('rating', models.PositiveIntegerField(validators=[django.core.validators.MaxValueValidator(5)])),
+                ('restaurant', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.restaurant')),
+            ],
+            options={
+                'verbose_name': 'Restaurant Review',
+                'verbose_name_plural': 'Restaurant Reviews',
+                'ordering': ['-rating'],
+                'abstract': False,
+                'unique_together': {('reviewer_name', 'restaurant')},
+            },
+        ),
+        migrations.DeleteModel(
+            name='RestaurantReview',
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/migrations/0007_menureview.py

@@ -0,0 +1,32 @@
+# Generated by Django 5.0.4 on 2024-07-19 12:56
+
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0006_foodcriticrestaurantreview_regularrestaurantreview_and_more'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='MenuReview',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('reviewer_name', models.CharField(max_length=100)),
+                ('review_content', models.TextField()),
+                ('rating', models.PositiveIntegerField(validators=[django.core.validators.MaxValueValidator(5)])),
+                ('menu', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.menu')),
+            ],
+            options={
+                'verbose_name': 'Menu Review',
+                'verbose_name_plural': 'Menu Reviews',
+                'ordering': ['-rating'],
+                'indexes': [models.Index(fields=['menu'], name='main_app_menu_review_menu_id')],
+                'unique_together': {('reviewer_name', 'menu')},
+            },
+        ),
+    ]

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/mixins.py

@@ -0,0 +1,12 @@
+from django.core.validators import MaxValueValidator
+from django.db import models
+
+
+class ReviewMixin(models.Model):
+    reviewer_name = models.CharField(max_length=100)
+    review_content = models.TextField()
+    rating = models.PositiveIntegerField(validators=[MaxValueValidator(5)])
+
+    class Meta:
+        abstract = True
+        ordering = ['-rating']

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/models.py

@@ -0,0 +1,75 @@
+from django.core.validators import MinLengthValidator, MaxLengthValidator, MinValueValidator, MaxValueValidator
+from django.db import models
+
+from main_app.mixins import ReviewMixin
+from main_app.validators import validate_menu_categories
+
+
+# Create your models here.
+
+
+class Restaurant(models.Model):
+    name = models.CharField(
+        max_length=100,
+        validators=[
+            MinLengthValidator(2, "Name must be at least 2 characters long."),
+            MaxLengthValidator(100, "Name cannot exceed 100 characters.")
+        ]
+    )
+    location = models.CharField(
+        max_length=200,
+        validators=[
+            MinLengthValidator(2, "Location must be at least 2 characters long."),
+            MaxLengthValidator(200, "Location cannot exceed 200 characters.")
+        ]
+    )
+    description = models.TextField(null=True, blank=True)
+    rating = models.DecimalField(max_digits=3, decimal_places=2,
+                                 validators=[
+                                     MinValueValidator(0.00, "Rating must be at least 0.00."),
+                                     MaxValueValidator(5.00, "Rating cannot exceed 5.00.")
+                                 ])
+
+
+class Menu(models.Model):
+    name = models.CharField(
+        max_length=100,
+    )
+    description = models.TextField(
+        validators=[validate_menu_categories(limit_value=["Appetizers", "Main Course","Desserts"],message='The menu must include each of the categories "Appetizers", "Main Course", "Desserts".')]
+    )
+    restaurant = models.ForeignKey(to='Restaurant', on_delete=models.CASCADE)
+
+
+class RestaurantReview(ReviewMixin):
+    restaurant = models.ForeignKey(to='Restaurant', on_delete=models.CASCADE)
+
+    class Meta(ReviewMixin.Meta):
+        verbose_name = 'Restaurant Review'
+        verbose_name_plural = 'Restaurant Reviews'
+        unique_together = ['reviewer_name', 'restaurant']
+        abstract = True
+
+
+
+class RegularRestaurantReview(RestaurantReview):
+    pass
+
+
+class FoodCriticRestaurantReview(RestaurantReview):
+    food_critic_cuisine_area = models.CharField(max_length=100)
+
+    class Meta(RestaurantReview.Meta):
+        verbose_name = 'Food Critic Review'
+        verbose_name_plural = 'Food Critic Reviews'
+
+
+class MenuReview(ReviewMixin):
+    menu = models.ForeignKey(to='Menu', on_delete=models.CASCADE)
+
+    class Meta(ReviewMixin.Meta):
+        verbose_name = 'Menu Review'
+        verbose_name_plural = 'Menu Reviews'
+        unique_together = ['reviewer_name', 'menu']
+        indexes = [models.Index(fields=('menu',), name='main_app_menu_review_menu_id')]
+

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/tests.py

@@ -0,0 +1,3 @@
+from django.test import TestCase
+
+# Create your tests here.

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/validators.py

@@ -0,0 +1,18 @@
+import django.core.validators
+from django.core.exceptions import ValidationError
+from django.core.validators import BaseValidator
+
+
+class validate_menu_categories(BaseValidator):
+
+    def __init__(self, *args, **kwargs):
+        kwargs['limit_value'] = kwargs.get('limit_value', ["Appetizers", "Main Course","Desserts"])
+        kwargs['message'] = kwargs.get('message','The menu must include each of the categories "Appetizers", "Main Course", "Desserts".')
+        self.includes = kwargs['limit_value']
+        self.message = kwargs['message']
+        super().__init__(*args,**kwargs)
+
+    def __call__(self, value):
+        for dish in self.includes:
+            if dish not in value:
+                raise ValidationError(self.message)

DataBases/PythonORM/advanced_django_model_techniques_lab/main_app/views.py

@@ -0,0 +1,3 @@
+from django.shortcuts import render
+
+# Create your views here.

DataBases/PythonORM/advanced_django_model_techniques_lab/manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()

DataBases/PythonORM/advanced_django_model_techniques_lab/orm_skeleton/asgi.py

@@ -0,0 +1,16 @@
+"""
+ASGI config for orm_skeleton project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_asgi_application()

DataBases/PythonORM/advanced_django_model_techniques_lab/orm_skeleton/settings.py

@@ -0,0 +1,135 @@
+"""
+Django settings for orm_skeleton project.
+
+Generated by 'django-admin startproject' using Django 4.2.4.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/4.2/ref/settings/
+"""
+
+from pathlib import Path
+
+# Build paths inside the project like this: BASE_DIR / 'subdir'.
+BASE_DIR = Path(__file__).resolve().parent.parent
+
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/4.2/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'django-insecure-cd%2g!p_@ut(kc8)%bd9_*@)i@kff^orkvy=!c#i!l+ak98)%0'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+
+# Application definition
+
+INSTALLED_APPS = [
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+    'main_app',
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+]
+
+ROOT_URLCONF = 'orm_skeleton.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [BASE_DIR / 'templates']
+        ,
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = 'orm_skeleton.wsgi.application'
+
+
+# Database
+# https://docs.djangoproject.com/en/4.2/ref/settings/#databases
+
+# DATABASES = {
+#     'default': {
+#         'ENGINE': 'django.db.backends.sqlite3',
+#         'NAME': BASE_DIR / 'db.sqlite3',
+#     }
+# }
+
+DATABASES = {
+    "default": {
+        "ENGINE": "django.db.backends.postgresql",
+        "NAME": "advanced_django_models_techniques_lab",
+        "USER": "postgres-user",
+        "PASSWORD": "password",
+        "HOST": "localhost",
+        "PORT": "5432",
+    }
+}
+
+# Password validation
+# https://docs.djangoproject.com/en/4.2/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+
+# Internationalization
+# https://docs.djangoproject.com/en/4.2/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_TZ = True
+
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/4.2/howto/static-files/
+
+STATIC_URL = 'static/'
+
+# Default primary key field type
+# https://docs.djangoproject.com/en/4.2/ref/settings/#default-auto-field
+
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

DataBases/PythonORM/advanced_django_model_techniques_lab/orm_skeleton/urls.py

@@ -0,0 +1,22 @@
+"""
+URL configuration for orm_skeleton project.
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/4.2/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  path('', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.urls import include, path
+    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
+"""
+from django.contrib import admin
+from django.urls import path
+
+urlpatterns = [
+    path('admin/', admin.site.urls),
+]

DataBases/PythonORM/advanced_django_model_techniques_lab/orm_skeleton/wsgi.py

@@ -0,0 +1,16 @@
+"""
+WSGI config for orm_skeleton project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_wsgi_application()

DataBases/PythonORM/advanced_queries_in_django_exercise/caller.py

@@ -0,0 +1,63 @@
+import os
+from datetime import date
+
+import django
+
+
+# Set up Django
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "orm_skeleton.settings")
+django.setup()
+
+# Import your models here
+from main_app.models import RealEstateListing, VideoGame, BillingInfo, Invoice, Programmer, Project, Technology, Task, \
+    Exercise
+
+# Run and print your queries
+
+if __name__ == '__main__':
+    Exercise.objects.all().delete()
+    # Create instances of Exercise
+    exercise1 = Exercise.objects.create(
+        name="Push-ups",
+        category="Strength",
+        difficulty_level=4,
+        duration_minutes=10,
+        repetitions=50,
+    )
+
+    exercise2 = Exercise.objects.create(
+        name="Running",
+        category="Cardio",
+        difficulty_level=7,
+        duration_minutes=20,
+        repetitions=0,
+    )
+
+    exercise3 = Exercise.objects.create(
+        name="Pull-ups",
+        category="Strength",
+        difficulty_level=13,
+        duration_minutes=35,
+        repetitions=20,
+    )
+
+    # Print the results
+    long_and_hard_exercises = Exercise.get_long_and_hard_exercises()
+    print("Long and hard exercises:")
+    for exercise in long_and_hard_exercises:
+        print('- ' + exercise.name)
+
+    short_and_easy_exercises = Exercise.get_short_and_easy_exercises()
+    print("Short and easy exercises:")
+    for exercise in short_and_easy_exercises:
+        print('- ' + exercise.name)
+
+    exercises_within_duration = Exercise.get_exercises_within_duration(20, 40)
+    print(f"Exercises within 20 - 40 minutes:")
+    for exercise in exercises_within_duration:
+        print('- ' + exercise.name)
+
+    exercises_with_difficulty_and_repetitions = Exercise.get_exercises_with_difficulty_and_repetitions(6, 15)
+    print(f"Exercises with difficulty 6+ and repetitions 15+:")
+    for exercise in exercises_with_difficulty_and_repetitions:
+        print('- ' + exercise.name)

DataBases/PythonORM/advanced_queries_in_django_exercise/main_app/admin.py

@@ -0,0 +1,3 @@
+from django.contrib import admin
+
+# Register your models here.

DataBases/PythonORM/advanced_queries_in_django_exercise/main_app/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+
+class MainAppConfig(AppConfig):
+    default_auto_field = 'django.db.models.BigAutoField'
+    name = 'main_app'

DataBases/PythonORM/advanced_queries_in_django_exercise/main_app/managers.py

@@ -0,0 +1,42 @@
+from decimal import Decimal
+
+from django.db import models
+from django.db.models import Count, Avg
+
+
+class RealEstateListingManager(models.Manager):
+    def by_property_type(self, property_type: str):
+        return self.filter(property_type=property_type)
+
+    def in_price_range(self, min_price: Decimal, max_price: Decimal):
+        return self.filter(price__range=(min_price,max_price))
+
+    def with_bedrooms(self, bedrooms_count: int):
+        return self.filter(bedrooms=bedrooms_count)
+
+    def popular_locations(self):
+        return self.values('location').annotate(location_count=Count('id')).order_by('-location_count','location')[:2]
+
+
+class VideoGameManager(models.Manager):
+    def games_by_genre(self, genre: str):
+        return self.filter(genre=genre)
+
+
+    def recently_released_games(self, year: int):
+        return self.filter(release_year__gte=year)
+
+
+    def highest_rated_game(self):
+        return self.all().order_by('-rating').first()
+
+
+    def lowest_rated_game(self):
+        return self.all().order_by('rating').first()
+
+
+    def average_rating(self):
+        return round(self.aggregate(avg_rating=Avg('rating'))['avg_rating'],1)
+
+
+

DataBases/PythonORM/advanced_queries_in_django_exercise/main_app/migrations/0001_initial.py

@@ -0,0 +1,102 @@
+# Generated by Django 5.0.4 on 2024-07-20 19:42
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='BillingInfo',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('address', models.CharField(max_length=200)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Exercise',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('category', models.CharField(max_length=50)),
+                ('difficulty_level', models.PositiveIntegerField()),
+                ('duration_minutes', models.PositiveIntegerField()),
+                ('repetitions', models.PositiveIntegerField()),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Project',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('description', models.TextField()),
+            ],
+        ),
+        migrations.CreateModel(
+            name='RealEstateListing',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('property_type', models.CharField(choices=[('House', 'House'), ('Flat', 'Flat'), ('Villa', 'Villa'), ('Cottage', 'Cottage'), ('Studio', 'Studio')], max_length=100)),
+                ('price', models.DecimalField(decimal_places=2, max_digits=10)),
+                ('bedrooms', models.PositiveIntegerField()),
+                ('location', models.CharField(max_length=100)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Task',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=200)),
+                ('description', models.TextField()),
+                ('priority', models.CharField(choices=[('Low', 'Low'), ('Medium', 'Medium'), ('High', 'High')], max_length=20)),
+                ('is_completed', models.BooleanField(default=False)),
+                ('creation_date', models.DateField()),
+                ('completion_date', models.DateField()),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Technology',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('description', models.TextField()),
+            ],
+        ),
+        migrations.CreateModel(
+            name='VideoGame',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=100)),
+                ('genre', models.CharField(choices=[('Action', 'Action'), ('RPG', 'RPG'), ('Adventure', 'Adventure'), ('Sports', 'Sports'), ('Strategy', 'Strategy')], max_length=100)),
+                ('release_year', models.PositiveIntegerField()),
+                ('rating', models.DecimalField(decimal_places=1, max_digits=2)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Invoice',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('invoice_number', models.CharField(max_length=20, unique=True)),
+                ('billing_info', models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, to='main_app.billinginfo')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Programmer',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('projects', models.ManyToManyField(related_name='programmers', to='main_app.project')),
+            ],
+        ),
+        migrations.AddField(
+            model_name='project',
+            name='technologies_used',
+            field=models.ManyToManyField(related_name='projects', to='main_app.technology'),
+        ),
+    ]

DataBases/PythonORM/advanced_queries_in_django_exercise/main_app/migrations/0002_alter_videogame_rating_alter_videogame_release_year.py

@@ -0,0 +1,24 @@
+# Generated by Django 5.0.4 on 2024-07-21 10:22
+
+import main_app.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='videogame',
+            name='rating',
+            field=models.DecimalField(decimal_places=1, max_digits=2, validators=[main_app.validators.InRangeValidator(0.0, 10.0, 'The rating must be between 0.0 and 10.0')]),
+        ),
+        migrations.AlterField(
+            model_name='videogame',
+            name='release_year',
+            field=models.PositiveIntegerField(validators=[main_app.validators.InRangeValidator(1990, 2023, 'The release year must be between 1990 and 2023')]),
+        ),
+    ]

DataBases/PythonORM/advanced_queries_in_django_exercise/main_app/models.py

@@ -0,0 +1,151 @@
+from datetime import timedelta
+
+from django.db import models
+from django.db.models import F, Q, Min, Max
+
+from main_app.managers import RealEstateListingManager, VideoGameManager
+from main_app.validators import InRangeValidator
+
+
+# Create your models here.
+
+
+class RealEstateListing(models.Model):
+    PROPERTY_TYPE_CHOICES = [
+        ('House', 'House'),
+        ('Flat', 'Flat'),
+        ('Villa', 'Villa'),
+        ('Cottage', 'Cottage'),
+        ('Studio', 'Studio'),
+    ]
+
+    property_type = models.CharField(max_length=100, choices=PROPERTY_TYPE_CHOICES)
+    price = models.DecimalField(max_digits=10, decimal_places=2)
+    bedrooms = models.PositiveIntegerField()
+    location = models.CharField(max_length=100)
+
+    objects = RealEstateListingManager()
+
+
+class VideoGame(models.Model):
+    GENRE_CHOICES = [
+        ('Action', 'Action'),
+        ('RPG', 'RPG'),
+        ('Adventure', 'Adventure'),
+        ('Sports', 'Sports'),
+        ('Strategy', 'Strategy'),
+    ]
+
+    title = models.CharField(max_length=100)
+    genre = models.CharField(max_length=100, choices=GENRE_CHOICES)
+    release_year = models.PositiveIntegerField(validators=[InRangeValidator(1990,2023, "The release year must be between 1990 and 2023")])
+    rating = models.DecimalField(max_digits=2,decimal_places=1, validators=[InRangeValidator(0.0,10.0,"The rating must be between 0.0 and 10.0")])
+
+    def __str__(self):
+        return self.title
+
+    objects = VideoGameManager()
+
+
+class BillingInfo(models.Model):
+    address = models.CharField(max_length=200)
+
+
+class Invoice(models.Model):
+    invoice_number = models.CharField(max_length=20, unique=True)
+    billing_info = models.OneToOneField(BillingInfo, on_delete=models.CASCADE)
+
+    @classmethod
+    def get_invoices_with_prefix(cls, prefix: str):
+        return cls.objects.filter(invoice_number__startswith=prefix)
+
+    @classmethod
+    def get_invoices_sorted_by_number(cls):
+        return cls.objects.all().order_by('invoice_number')
+
+    @classmethod
+    def get_invoice_with_billing_info(cls, invoice_number: str):
+        return cls.objects.get(invoice_number=invoice_number)
+
+
+
+
+class Technology(models.Model):
+    name = models.CharField(max_length=100)
+    description = models.TextField()
+
+
+class Project(models.Model):
+    name = models.CharField(max_length=100)
+    description = models.TextField()
+    technologies_used = models.ManyToManyField(Technology, related_name='projects')
+
+    def get_programmers_with_technologies(self):
+        return self.programmers.prefetch_related('projects__technologies_used')
+
+
+class Programmer(models.Model):
+    name = models.CharField(max_length=100)
+    projects = models.ManyToManyField(Project, related_name='programmers')
+
+    def get_projects_with_technologies(self):
+        return self.projects.prefetch_related('technologies_used')
+
+
+class Task(models.Model):
+    PRIORITIES = (
+        ('Low', 'Low'),
+        ('Medium', 'Medium'),
+        ('High', 'High')
+    )
+
+    title = models.CharField(max_length=200)
+    description = models.TextField()
+    priority = models.CharField(max_length=20, choices=PRIORITIES)
+    is_completed = models.BooleanField(default=False)
+    creation_date = models.DateField()
+    completion_date = models.DateField()
+
+    @classmethod
+    def ongoing_high_priority_tasks(cls):
+        return cls.objects.filter(priority='High', is_completed=False, completion_date__gt=F('creation_date'))
+
+    @classmethod
+    def completed_mid_priority_tasks(cls):
+        return cls.objects.filter(priority='Medium', is_completed=True)
+
+    @classmethod
+    def search_tasks(cls, query: str):
+        return cls.objects.filter((Q(title__icontains=query) | Q(description__icontains=query)))
+
+    @classmethod
+    def recent_completed_tasks(cls, days: int):
+        return cls.objects.filter(is_completed=True, completion_date__gte=F('creation_date') - timedelta(days=days))
+
+
+
+
+class Exercise(models.Model):
+    name = models.CharField(max_length=100)
+    category = models.CharField(max_length=50)
+    difficulty_level = models.PositiveIntegerField()
+    duration_minutes = models.PositiveIntegerField()
+    repetitions = models.PositiveIntegerField()
+
+
+    @classmethod
+    def get_long_and_hard_exercises(cls):
+        return cls.objects.filter(duration_minutes__gt=30, difficulty_level__gte=10)
+
+    @classmethod
+    def get_short_and_easy_exercises(cls):
+        return cls.objects.filter(duration_minutes__lt=15, difficulty_level__lt=5)
+
+    @classmethod
+    def get_exercises_within_duration(cls, min_duration: int, max_duration: int):
+        return cls.objects.filter(duration_minutes__gte=min_duration, duration_minutes__lte=max_duration)
+
+    @classmethod
+    def get_exercises_with_difficulty_and_repetitions(cls, min_difficulty: int, min_repetitions: int):
+        return cls.objects.filter((Q(difficulty_level__gte=min_difficulty) & Q(repetitions__gte=min_repetitions)))
+

DataBases/PythonORM/advanced_queries_in_django_exercise/main_app/tests.py

@@ -0,0 +1,3 @@
+from django.test import TestCase
+
+# Create your tests here.

DataBases/PythonORM/advanced_queries_in_django_exercise/main_app/validators.py

@@ -0,0 +1,16 @@
+from decimal import Decimal
+
+from django.core.exceptions import ValidationError
+from django.core.validators import BaseValidator
+
+
+class InRangeValidator(BaseValidator):
+
+    def __init__(self, min_value, max_value, message=None):
+        super().__init__(None, message)
+        self.min_value = min_value
+        self.max_value = max_value
+
+    def __call__(self, value):
+        if not self.min_value <= value <= self.max_value:
+            raise ValidationError(self.message)

DataBases/PythonORM/advanced_queries_in_django_exercise/main_app/views.py

@@ -0,0 +1,3 @@
+from django.shortcuts import render
+
+# Create your views here.

DataBases/PythonORM/advanced_queries_in_django_exercise/manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()

DataBases/PythonORM/advanced_queries_in_django_exercise/orm_skeleton/asgi.py

@@ -0,0 +1,16 @@
+"""
+ASGI config for orm_skeleton project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_asgi_application()

DataBases/PythonORM/advanced_queries_in_django_exercise/orm_skeleton/settings.py

@@ -0,0 +1,158 @@
+"""
+Django settings for orm_skeleton project.
+
+Generated by 'django-admin startproject' using Django 4.2.4.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/4.2/ref/settings/
+"""
+
+from pathlib import Path
+
+# Build paths inside the project like this: BASE_DIR / 'subdir'.
+BASE_DIR = Path(__file__).resolve().parent.parent
+
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/4.2/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'django-insecure-cd%2g!p_@ut(kc8)%bd9_*@)i@kff^orkvy=!c#i!l+ak98)%0'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+
+# Application definition
+
+INSTALLED_APPS = [
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+    'main_app',
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+]
+
+ROOT_URLCONF = 'orm_skeleton.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [BASE_DIR / 'templates']
+        ,
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = 'orm_skeleton.wsgi.application'
+
+
+# Database
+# https://docs.djangoproject.com/en/4.2/ref/settings/#databases
+
+# DATABASES = {
+#     'default': {
+#         'ENGINE': 'django.db.backends.sqlite3',
+#         'NAME': BASE_DIR / 'db.sqlite3',
+#     }
+# }
+
+DATABASES = {
+    "default": {
+        "ENGINE": "django.db.backends.postgresql",
+        "NAME": "advanced_queries_in_django_exercise",
+        "USER": "postgres-user",
+        "PASSWORD": "password",
+        "HOST": "localhost",
+        "PORT": "5432",
+    }
+}
+
+
+
+# Password validation
+# https://docs.djangoproject.com/en/4.2/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+
+# Internationalization
+# https://docs.djangoproject.com/en/4.2/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_TZ = True
+
+LOGGING = {
+    'version': 1,
+    'disable_existing_loggers': False,
+    'handlers': {
+        'console': {
+            'class': 'logging.StreamHandler',
+        },
+    },
+    'root': {
+        'handlers': ['console'],
+        'level': 'DEBUG',  # Other levels CRITICAL, ERROR, WARNING, INFO, DEBUG
+    },
+    'loggers': {
+        'django.db.backends': {  # responsible for the sql logs
+            'handlers': ['console'],
+            'level': 'DEBUG',
+            'propagate': False,
+        },
+    },
+}
+
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/4.2/howto/static-files/
+
+STATIC_URL = 'static/'
+
+# Default primary key field type
+# https://docs.djangoproject.com/en/4.2/ref/settings/#default-auto-field
+
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

DataBases/PythonORM/advanced_queries_in_django_exercise/orm_skeleton/urls.py

@@ -0,0 +1,22 @@
+"""
+URL configuration for orm_skeleton project.
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/4.2/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  path('', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.urls import include, path
+    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
+"""
+from django.contrib import admin
+from django.urls import path
+
+urlpatterns = [
+    path('admin/', admin.site.urls),
+]

DataBases/PythonORM/advanced_queries_in_django_exercise/orm_skeleton/wsgi.py

@@ -0,0 +1,16 @@
+"""
+WSGI config for orm_skeleton project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_wsgi_application()

DataBases/PythonORM/advanced_queries_in_django_lab/caller.py

@@ -0,0 +1,104 @@
+import os
+from decimal import Decimal
+
+import django
+from django.db.models import Sum, F, Q
+
+# Set up Django
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "orm_skeleton.settings")
+django.setup()
+
+# Import your models
+from main_app.models import Product, Category, Customer, Order, OrderProduct
+
+
+# Create and run queries
+def add_records_to_database():
+    # Categories
+    food_category = Category.objects.create(name='Food')
+    drinks_category = (Category.objects.create(name='Drinks'))
+
+    # Food
+    product1 = Product.objects.create(name='Pizza', description='Delicious pizza with toppings', price=10.99, category=food_category, is_available=False)
+    product2 = Product.objects.create(name='Burger', description='Classic burger with cheese and fries', price=7.99, category=food_category, is_available=False)
+    product3 = Product.objects.create(name='Apples', description='A bag of juicy red apples', price=3.99, category=food_category, is_available=True)
+    product4 = Product.objects.create(name='Bread', description='A freshly baked loaf of bread', price=2.49, category=food_category, is_available=True)
+    product5 = Product.objects.create(name='Pasta and Sauce Bundle', description='Package containing pasta and a jar of pasta sauce', price=6.99, category=food_category, is_available=False)
+    product6 = Product.objects.create(name='Tomatoes', description='A bundle of ripe, red tomatoes', price=2.99, category=food_category, is_available=True)
+    product7 = Product.objects.create(name='Carton of Eggs', description='A carton containing a dozen fresh eggs', price=3.49, category=food_category, is_available=True)
+    product8 = Product.objects.create(name='Cheddar Cheese', description='A block of aged cheddar cheese', price=7.99, category=food_category, is_available=False)
+    product9 = Product.objects.create(name='Milk', description='A gallon of fresh cow milk', price=3.49, category=food_category, is_available=True)
+
+    # Drinks
+    product10 = Product.objects.create(name='Coca Cola', description='Refreshing cola drink', price=1.99, category=drinks_category, is_available=True)
+    product11 = Product.objects.create(name='Orange Juice', description='Freshly squeezed orange juice', price=2.49, category=drinks_category, is_available=False)
+    product12 = Product.objects.create(name='Bottled Water', description='A 12-pack of purified bottled water', price=4.99, category=drinks_category, is_available=True)
+    product13 = Product.objects.create(name='Orange Soda', description='A 6-pack of carbonated orange soda', price=5.49, category=drinks_category, is_available=True)
+    product14 = Product.objects.create(name='Bottled Green Tea', description='A bottled green tea', price=3.99, category=drinks_category, is_available=False)
+    product15 = Product.objects.create(name='Beer', description='A bottled craft beer', price=5.49, category=drinks_category, is_available=True)
+
+    # Customers
+    customer1 = Customer.objects.create(username='john_doe')
+    customer2 = Customer.objects.create(username='alex_alex')
+    customer3 = Customer.objects.create(username='peter132')
+    customer4 = Customer.objects.create(username='k.k.')
+    customer5 = Customer.objects.create(username='peter_smith')
+
+    # Orders
+    order1 = Order.objects.create(customer=customer1)
+    order_product1 = OrderProduct.objects.create(order=order1, product=product3, quantity=2)
+    order_product2 = OrderProduct.objects.create(order=order1, product=product6, quantity=1)
+    order_product3 = OrderProduct.objects.create(order=order1, product=product7, quantity=5)
+    order_product4 = OrderProduct.objects.create(order=order1, product=product13, quantity=1)
+
+    order2 = Order.objects.create(customer=customer3)
+    order_product5 = OrderProduct.objects.create(order=order2, product=product3, quantity=2)
+    order_product6 = OrderProduct.objects.create(order=order2, product=product9, quantity=1)
+
+    order3 = Order.objects.create(customer=customer1)
+    order_product5 = OrderProduct.objects.create(order=order3, product=product12, quantity=4)
+    order_product6 = OrderProduct.objects.create(order=order3, product=product7, quantity=3)
+    return "All data entered!"
+
+
+# Run and print your queries
+# print(add_records_to_database())
+
+def product_quantity_ordered():
+    return '\n'.join(f'Quantity ordered of {product.name}: {product.total_ordered_quantity}' for product in Product.objects.annotate(total_ordered_quantity = Sum('orderproduct__quantity')).exclude(total_ordered_quantity=None).order_by('-total_ordered_quantity'))
+
+
+def ordered_products_per_customer():
+    result = []
+    for order in Order.objects.prefetch_related('orderproduct_set__product__category').order_by('id'):
+        result.append(f'Order ID: {order.id}, Customer: {order.customer.username}')
+        for product in order.orderproduct_set.all():
+            result.append(f'- Product: {product.product.name}, Category: {product.product.category.name}')
+    return '\n'.join(result)
+
+
+def filter_products():
+    return '\n'.join(
+        f'{product.name}: {product.price}lv.' for product in
+        Product.objects.filter(Q(is_available=True) & Q(price__gt=3.00)).order_by('-price','name')
+    )
+
+
+def give_discount():
+    Product.objects.filter(is_available=True, price__gt=3.00).update(price=(F('price') * 0.70))
+    return '\n'.join(
+        f'{product.name}: {product.price}lv.' for product in \
+        Product.objects.filter(is_available=True).order_by('-price', 'name'))
+
+
+
+
+
+
+if __name__ == '__main__':
+    Product.objects.all().delete()
+    Order.objects.all().delete()
+    Customer.objects.all().delete()
+    Category.objects.all().delete()
+    add_records_to_database()
+    print(give_discount())

DataBases/PythonORM/advanced_queries_in_django_lab/main_app/admin.py

@@ -0,0 +1,3 @@
+from django.contrib import admin
+
+# Register your models here.

DataBases/PythonORM/advanced_queries_in_django_lab/main_app/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+
+class MainAppConfig(AppConfig):
+    default_auto_field = 'django.db.models.BigAutoField'
+    name = 'main_app'

DataBases/PythonORM/advanced_queries_in_django_lab/main_app/managers.py

@@ -0,0 +1,11 @@
+from django.db import models
+
+
+class ProductManager(models.Manager):
+
+    def available_products(self):
+        return self.filter(is_available=True)
+
+    def available_products_in_category(self, category_name: str):
+        return self.filter(category__name=category_name, is_available=True)
+

DataBases/PythonORM/advanced_queries_in_django_lab/main_app/migrations/0001_initial.py

@@ -0,0 +1,61 @@
+# Generated by Django 5.0.4 on 2024-07-20 13:09
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Category',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Customer',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('username', models.CharField(max_length=50, unique=True)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Order',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('customer', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.customer')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Product',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('description', models.TextField(blank=True, null=True)),
+                ('price', models.DecimalField(decimal_places=2, max_digits=10)),
+                ('is_available', models.BooleanField(default=True)),
+                ('category', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.category')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='OrderProduct',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('quantity', models.PositiveIntegerField()),
+                ('order', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.order')),
+                ('product', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.product')),
+            ],
+        ),
+        migrations.AddField(
+            model_name='order',
+            name='products',
+            field=models.ManyToManyField(through='main_app.OrderProduct', to='main_app.product'),
+        ),
+    ]

DataBases/PythonORM/advanced_queries_in_django_lab/main_app/models.py

@@ -0,0 +1,35 @@
+from django.db import models
+
+from main_app.managers import ProductManager
+
+
+class Category(models.Model):
+    name = models.CharField(max_length=100)
+
+
+class Product(models.Model):
+    name = models.CharField(max_length=100)
+    description = models.TextField(null=True, blank=True)
+    price = models.DecimalField(max_digits=10, decimal_places=2)
+    category = models.ForeignKey(Category, on_delete=models.CASCADE)
+    is_available = models.BooleanField(default=True)
+
+    def __str__(self):
+        return f"{self.category.name}: {self.name}"
+
+    objects = ProductManager()
+
+
+class Customer(models.Model):
+    username = models.CharField(max_length=50, unique=True)
+
+
+class Order(models.Model):
+    customer = models.ForeignKey(Customer, on_delete=models.CASCADE)
+    products = models.ManyToManyField(Product, through='OrderProduct')
+
+
+class OrderProduct(models.Model):
+    order = models.ForeignKey(Order, on_delete=models.CASCADE)
+    product = models.ForeignKey(Product, on_delete=models.CASCADE)
+    quantity = models.PositiveIntegerField()

DataBases/PythonORM/advanced_queries_in_django_lab/main_app/views.py

@@ -0,0 +1,3 @@
+from django.shortcuts import render
+
+# Create your views here.

DataBases/PythonORM/advanced_queries_in_django_lab/manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()

DataBases/PythonORM/advanced_queries_in_django_lab/orm_skeleton/asgi.py

@@ -0,0 +1,16 @@
+"""
+ASGI config for orm_skeleton project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_asgi_application()

DataBases/PythonORM/advanced_queries_in_django_lab/orm_skeleton/settings.py

@@ -0,0 +1,136 @@
+"""
+Django settings for orm_skeleton project.
+
+Generated by 'django-admin startproject' using Django 4.2.4.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/4.2/ref/settings/
+"""
+
+from pathlib import Path
+
+# Build paths inside the project like this: BASE_DIR / 'subdir'.
+BASE_DIR = Path(__file__).resolve().parent.parent
+
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/4.2/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'django-insecure-cd%2g!p_@ut(kc8)%bd9_*@)i@kff^orkvy=!c#i!l+ak98)%0'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+
+# Application definition
+
+INSTALLED_APPS = [
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+    'main_app',
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+]
+
+ROOT_URLCONF = 'orm_skeleton.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [BASE_DIR / 'templates']
+        ,
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = 'orm_skeleton.wsgi.application'
+
+
+# Database
+# https://docs.djangoproject.com/en/4.2/ref/settings/#databases
+
+# DATABASES = {
+#     'default': {
+#         'ENGINE': 'django.db.backends.sqlite3',
+#         'NAME': BASE_DIR / 'db.sqlite3',
+#     }
+# }
+
+DATABASES = {
+    "default": {
+        "ENGINE": "django.db.backends.postgresql",
+        "NAME": "advanced_queries_in_django_lab",
+        "USER": "postgres-user",
+        "PASSWORD": "password",
+        "HOST": "localhost",
+        "PORT": "5432",
+    }
+}
+
+
+# Password validation
+# https://docs.djangoproject.com/en/4.2/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+
+# Internationalization
+# https://docs.djangoproject.com/en/4.2/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_TZ = True
+
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/4.2/howto/static-files/
+
+STATIC_URL = 'static/'
+
+# Default primary key field type
+# https://docs.djangoproject.com/en/4.2/ref/settings/#default-auto-field
+
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

DataBases/PythonORM/advanced_queries_in_django_lab/orm_skeleton/urls.py

@@ -0,0 +1,22 @@
+"""
+URL configuration for orm_skeleton project.
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/4.2/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  path('', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.urls import include, path
+    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
+"""
+from django.contrib import admin
+from django.urls import path
+
+urlpatterns = [
+    path('admin/', admin.site.urls),
+]

DataBases/PythonORM/advanced_queries_in_django_lab/orm_skeleton/wsgi.py

@@ -0,0 +1,16 @@
+"""
+WSGI config for orm_skeleton project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_wsgi_application()

DataBases/PythonORM/advanced_queries_in_django_lab/test_caller.py

@@ -0,0 +1,57 @@
+from django.test import TestCase
+from caller import give_discount
+from main_app.models import Category, Product, Customer, Order, OrderProduct
+
+class OrderedProductsPerCustomerTestCase(TestCase):
+    def setUp(self):
+        # Categories
+        food_category = Category.objects.create(name='Food')
+        drinks_category = (Category.objects.create(name='Drinks'))
+
+        # Food
+        product1 = Product.objects.create(name='Pizza', description='Delicious pizza with toppings', price=10.99,
+                                          category=food_category, is_available=False)
+        product2 = Product.objects.create(name='Burger', description='Classic burger with cheese and fries', price=7.99,
+                                          category=food_category, is_available=False)
+        product3 = Product.objects.create(name='Apples', description='A bag of juicy red apples', price=3.99,
+                                          category=food_category, is_available=True)
+        product4 = Product.objects.create(name='Bread', description='A freshly baked loaf of bread', price=2.49,
+                                          category=food_category, is_available=True)
+        product5 = Product.objects.create(name='Pasta and Sauce Bundle',
+                                          description='Package containing pasta and a jar of pasta sauce', price=6.99,
+                                          category=food_category, is_available=False)
+        product6 = Product.objects.create(name='Tomatoes', description='A bundle of ripe, red tomatoes', price=2.99,
+                                          category=food_category, is_available=True)
+        product7 = Product.objects.create(name='Carton of Eggs', description='A carton containing a dozen fresh eggs',
+                                          price=3.49, category=food_category, is_available=True)
+        product8 = Product.objects.create(name='Cheddar Cheese', description='A block of aged cheddar cheese',
+                                          price=7.99, category=food_category, is_available=False)
+        product9 = Product.objects.create(name='Milk', description='A gallon of fresh cow milk', price=3.49,
+                                          category=food_category, is_available=True)
+
+        # Drinks
+        product10 = Product.objects.create(name='Coca Cola', description='Refreshing cola drink', price=1.99,
+                                           category=drinks_category, is_available=True)
+        product11 = Product.objects.create(name='Orange Juice', description='Freshly squeezed orange juice', price=2.49,
+                                           category=drinks_category, is_available=False)
+        product12 = Product.objects.create(name='Bottled Water', description='A 12-pack of purified bottled water',
+                                           price=4.99, category=drinks_category, is_available=True)
+        product13 = Product.objects.create(name='Orange Soda', description='A 6-pack of carbonated orange soda',
+                                           price=5.49, category=drinks_category, is_available=True)
+        product14 = Product.objects.create(name='Bottled Green Tea', description='A bottled green tea', price=3.99,
+                                           category=drinks_category, is_available=False)
+        product15 = Product.objects.create(name='Beer', description='A bottled craft beer', price=5.49,
+                                           category=drinks_category, is_available=True)
+
+
+    def test_practice_test(self):
+        result = give_discount()
+        self.assertEqual(result.strip(), """Beer: 3.84lv.
+Orange Soda: 3.84lv.
+Bottled Water: 3.49lv.
+Tomatoes: 2.99lv.
+Apples: 2.79lv.
+Bread: 2.49lv.
+Carton of Eggs: 2.44lv.
+Milk: 2.44lv.
+Coca Cola: 1.99lv.""")

DataBases/PythonORM/exam_prep_I/caller.py

@@ -0,0 +1,61 @@
+import os
+import django
+from django.db.models import Q, Count, Avg, F
+
+# Set up Django
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "orm_skeleton.settings")
+django.setup()
+
+# Import your models here
+from main_app.models import Director, Actor, Movie
+
+
+# Create queries within functions
+def get_directors(search_name=None, search_nationality=None):
+    search = dict(filter(lambda x: x[1],{
+        "full_name__icontains": search_name,
+        "nationality__icontains": search_nationality
+    }.items()))
+    return '\n'.join(f"Director: {d.full_name}, nationality: {d.nationality}, experience: {d.years_of_experience}" for d in Director.objects.filter(**search).order_by('full_name')) or ""
+
+
+
+
+def get_top_director():
+    best_director = Director.objects.get_directors_by_movies_count().first()
+    return f"Top Director: {best_director.full_name}, movies: {best_director.movies_count}." if best_director else ""
+
+
+def get_top_actor():
+    top_actor = Actor.objects.prefetch_related('movies').annotate(movies_starred=Count('movies')).annotate(average_rating=Avg('movies__rating')).order_by('-movies_starred', "full_name").first()
+    return f"Top Actor: {top_actor.full_name}, starring in movies: {', '.join(m.title for m in top_actor.movies.all())}, movies average rating: {top_actor.average_rating:.1f}" if top_actor and top_actor.movies.count() else ""
+
+
+
+def get_actors_by_movies_count():
+    top_actors = Actor.objects.annotate(count_participations=Count('movie')).filter(count_participations__gt=0).order_by('-count_participations', 'full_name')[:3]
+    return '\n'.join(f"{a.full_name}, participated in {a.count_participations} movies" for a in top_actors) if top_actors else ""
+
+
+def get_top_rated_awarded_movie():
+    top_movie = Movie.objects.select_related('starring_actor').prefetch_related("actors").filter(is_awarded=True).order_by('-rating','title').first()
+    return f"Top rated awarded movie: {top_movie.title}, rating: {top_movie.rating:.1f}. Starring actor: {top_movie.starring_actor.full_name if top_movie.starring_actor else 'N/A'}. Cast: {', '.join(a.full_name for a in top_movie.actors.all().order_by('full_name'))}." if top_movie else ""
+
+
+def increase_rating():
+    updated = Movie.objects.filter(is_classic=True, rating__lte=9.9).update(rating=F('rating') + 0.1)
+    return f"Rating increased for {updated} movies." if updated else "No ratings increased."
+
+
+
+
+
+if __name__ == '__main__':
+    pass
+    # print(Director.objects.get_directors_by_movies_count())
+    # print(get_directors(None, 'zear'))
+    # print(get_top_director())
+    # print(get_top_actor())
+    # print(get_actors_by_movies_count())
+    # print(get_top_rated_awarded_movie())
+    print(increase_rating())

DataBases/PythonORM/exam_prep_I/main_app/admin.py

@@ -0,0 +1,30 @@
+from django.contrib import admin
+
+from main_app.models import Director, Actor, Movie
+
+
+# Register your models here.
+
+@admin.register(Director)
+class DirectorAdmin(admin.ModelAdmin):
+    list_display = ['full_name', 'birth_date', 'nationality']
+    list_filter = ['years_of_experience' ]
+    search_fields = ['full_name', 'nationality' ]
+
+
+
+@admin.register(Actor)
+class ActorAdmin(admin.ModelAdmin):
+    list_display = ['full_name', 'birth_date', 'nationality']
+    list_filter = ['is_awarded']
+    search_fields = ['full_name']
+    readonly_fields = ['last_updated']
+
+
+@admin.register(Movie)
+class MovieAdmin(admin.ModelAdmin):
+    list_display = ['title', 'storyline', 'rating', 'director']
+    list_filter = ['is_awarded', 'is_classic', 'genre']
+    search_fields = ['title' , 'director__full_name']
+    readonly_fields = ['last_updated']
+    search_help_text = 'Search by movie\'s title or director\'s name'

DataBases/PythonORM/exam_prep_I/main_app/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+
+class MainAppConfig(AppConfig):
+    default_auto_field = 'django.db.models.BigAutoField'
+    name = 'main_app'

DataBases/PythonORM/exam_prep_I/main_app/managers.py

@@ -0,0 +1,7 @@
+from django.db import models
+from django.db.models import Count
+
+class DirectorManager(models.Manager):
+
+    def get_directors_by_movies_count(self):
+        return self.all().annotate(movies_count=Count('movie')).order_by('-movies_count', 'full_name')

DataBases/PythonORM/exam_prep_I/main_app/migrations/0001_initial.py

@@ -0,0 +1,54 @@
+# Generated by Django 5.0.4 on 2024-08-02 12:39
+
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Actor',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('full_name', models.CharField(max_length=120, validators=[django.core.validators.MinLengthValidator(2)])),
+                ('birth_date', models.DateField(default='1900-01-01')),
+                ('nationality', models.CharField(default='Unknown', max_length=50)),
+                ('is_awarded', models.BooleanField(default=False)),
+                ('last_updated', models.DateTimeField(auto_now=True)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Director',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('full_name', models.CharField(max_length=120, validators=[django.core.validators.MinLengthValidator(2)])),
+                ('birth_date', models.DateField(default='1900-01-01')),
+                ('nationality', models.CharField(default='Unknown', max_length=50)),
+                ('years_of_experience', models.SmallIntegerField(validators=[django.core.validators.MinValueValidator(0)])),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Movie',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=150, validators=[django.core.validators.MinLengthValidator(5)])),
+                ('release_date', models.DateField()),
+                ('storyline', models.TextField(blank=True, null=True)),
+                ('genre', models.CharField(choices=[('Action', 'Action'), ('Comedy', 'Comedy'), ('Drama', 'Drama'), ('Other', 'Other')], default='Other', max_length=6)),
+                ('rating', models.DecimalField(decimal_places=1, default=0.0, max_digits=3, validators=[django.core.validators.MinValueValidator(0.0), django.core.validators.MaxValueValidator(10.0)])),
+                ('is_classic', models.BooleanField(default=False)),
+                ('is_awarded', models.BooleanField(default=False)),
+                ('last_updated', models.DateTimeField(auto_now=True)),
+                ('actors', models.ManyToManyField(to='main_app.actor')),
+                ('director', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.director')),
+                ('starring_actor', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='movies', to='main_app.actor')),
+            ],
+        ),
+    ]

DataBases/PythonORM/exam_prep_I/main_app/migrations/0002_alter_director_years_of_experience.py

@@ -0,0 +1,19 @@
+# Generated by Django 5.0.4 on 2024-08-02 12:42
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='director',
+            name='years_of_experience',
+            field=models.SmallIntegerField(default=0, validators=[django.core.validators.MinValueValidator(0)]),
+        ),
+    ]

DataBases/PythonORM/exam_prep_I/main_app/models.py

@@ -0,0 +1,54 @@
+from django.core.validators import MinLengthValidator, MinValueValidator, MaxValueValidator
+from django.db import models
+
+from main_app.managers import DirectorManager
+
+
+# Create your models here.
+
+class Director(models.Model):
+    full_name = models.CharField(max_length=120, validators=[MinLengthValidator(2)])
+    birth_date = models.DateField(default='1900-01-01')
+    nationality = models.CharField(max_length=50, default='Unknown')
+    years_of_experience = models.SmallIntegerField(validators=[MinValueValidator(0)], default=0)
+
+    def __str__(self):
+        return self.full_name
+
+    objects = DirectorManager()
+
+
+
+class Actor(models.Model):
+    full_name = models.CharField(max_length=120, validators=[MinLengthValidator(2)])
+    birth_date = models.DateField(default='1900-01-01')
+    nationality = models.CharField(max_length=50, default='Unknown')
+    is_awarded = models.BooleanField(default=False)
+    last_updated = models.DateTimeField(auto_now=True)
+
+    def __str__(self):
+        return self.full_name
+
+
+class Movie(models.Model):
+
+    class GenreChoices(models.TextChoices):
+        ACTION = 'Action','Action'
+        COMEDY = 'Comedy','Comedy'
+        DRAMA = 'Drama','Drama'
+        OTHER = 'Other','Other'
+
+    title = models.CharField(max_length=150, validators=[MinLengthValidator(5)])
+    release_date = models.DateField()
+    storyline = models.TextField(blank=True, null=True)
+    genre = models.CharField(max_length=6, default='Other', choices=GenreChoices)
+    rating = models.DecimalField(max_digits=3, decimal_places=1, validators=[MinValueValidator(0.0), MaxValueValidator(10.0)], default=0.0)
+    is_classic = models.BooleanField(default=False)
+    is_awarded = models.BooleanField(default=False)
+    last_updated = models.DateTimeField(auto_now=True)
+    director = models.ForeignKey(to='Director', on_delete=models.CASCADE)
+    starring_actor = models.ForeignKey(null=True, blank=True, to='Actor', on_delete=models.SET_NULL, related_name='movies')
+    actors = models.ManyToManyField(to='Actor')
+
+    def __str__(self):
+        return self.title

DataBases/PythonORM/exam_prep_I/main_app/tests.py

@@ -0,0 +1,3 @@
+from django.test import TestCase
+
+# Create your tests here.

DataBases/PythonORM/exam_prep_I/main_app/views.py

@@ -0,0 +1,3 @@
+from django.shortcuts import render
+
+# Create your views here.

DataBases/PythonORM/exam_prep_I/manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()

DataBases/PythonORM/exam_prep_I/orm_skeleton/asgi.py

@@ -0,0 +1,16 @@
+"""
+ASGI config for orm_skeleton project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_asgi_application()

DataBases/PythonORM/exam_prep_I/orm_skeleton/settings.py

@@ -0,0 +1,156 @@
+"""
+Django settings for orm_skeleton project.
+
+Generated by 'django-admin startproject' using Django 4.2.4.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/4.2/ref/settings/
+"""
+
+from pathlib import Path
+
+# Build paths inside the project like this: BASE_DIR / 'subdir'.
+BASE_DIR = Path(__file__).resolve().parent.parent
+
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/4.2/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = 'django-insecure-cd%2g!p_@ut(kc8)%bd9_*@)i@kff^orkvy=!c#i!l+ak98)%0'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+
+# Application definition
+
+INSTALLED_APPS = [
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+    'main_app',
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+]
+
+ROOT_URLCONF = 'orm_skeleton.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [BASE_DIR / 'templates']
+        ,
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = 'orm_skeleton.wsgi.application'
+
+
+# Database
+# https://docs.djangoproject.com/en/4.2/ref/settings/#databases
+
+# DATABASES = {
+#     'default': {
+#         'ENGINE': 'django.db.backends.sqlite3',
+#         'NAME': BASE_DIR / 'db.sqlite3',
+#     }
+# }
+
+DATABASES = {
+    "default": {
+        "ENGINE": "django.db.backends.postgresql",
+        "NAME": "exam_prep_i",
+        "USER": "postgres-user",
+        "PASSWORD": "password",
+        "HOST": "localhost",
+        "PORT": "5432",
+    }
+}
+
+# Password validation
+# https://docs.djangoproject.com/en/4.2/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+
+# Internationalization
+# https://docs.djangoproject.com/en/4.2/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_TZ = True
+
+LOGGING = {
+    'version': 1,
+    'disable_existing_loggers': False,
+    'handlers': {
+        'console': {
+            'class': 'logging.StreamHandler',
+        },
+    },
+    'root': {
+        'handlers': ['console'],
+        'level': 'DEBUG',  # Other levels CRITICAL, ERROR, WARNING, INFO, DEBUG
+    },
+    'loggers': {
+        'django.db.backends': {  # responsible for the sql logs
+            'handlers': ['console'],
+            'level': 'DEBUG',
+            'propagate': False,
+        },
+    },
+}
+
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/4.2/howto/static-files/
+
+STATIC_URL = 'static/'
+
+# Default primary key field type
+# https://docs.djangoproject.com/en/4.2/ref/settings/#default-auto-field
+
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

DataBases/PythonORM/exam_prep_I/orm_skeleton/urls.py

@@ -0,0 +1,22 @@
+"""
+URL configuration for orm_skeleton project.
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/4.2/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  path('', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.urls import include, path
+    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
+"""
+from django.contrib import admin
+from django.urls import path
+
+urlpatterns = [
+    path('admin/', admin.site.urls),
+]

DataBases/PythonORM/exam_prep_I/orm_skeleton/wsgi.py

@@ -0,0 +1,16 @@
+"""
+WSGI config for orm_skeleton project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_wsgi_application()

DataBases/PythonORM/exam_prep_II/caller.py

@@ -0,0 +1,67 @@
+import os
+import django
+from django.db.models import Q, Count, F, When, Case, Value
+
+# Set up Django
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "orm_skeleton.settings")
+django.setup()
+
+# Import your models here
+
+from main_app.models import Profile, Order, Product
+
+
+# Create queries within functions
+
+def get_profiles(search_string=None):
+    if search_string is None: return ""
+    profiles = Profile.objects.filter(Q(full_name__icontains=search_string) | Q(email__icontains=search_string) | Q(phone_number__icontains=search_string)).annotate(orders_count=Count('order')).order_by('full_name')
+    return '\n'.join(f'Profile: {p.full_name}, email: {p.email}, phone number: {p.phone_number}, orders: {p.orders_count}' for p in profiles) if len(profiles) else ""
+
+def get_loyal_profiles():
+    profiles = Profile.objects.get_regular_customers()
+    return '\n'.join(f'Profile: {p.full_name}, orders: {p.order_count}' for p in profiles) if len(profiles) else ""
+
+def get_last_sold_products():
+    order = Order.objects.prefetch_related('products').last()
+    return f"Last sold products: {', '.join(p.name for p in order.products.all().order_by('name'))}" if order else ""
+
+
+def get_top_products():
+    recent_products = Product.objects.annotate(sales_count=Count('order')).filter(sales_count__gt=0).order_by('-sales_count','name')[:5]
+    result = "Top products:\n" +"\n".join(f"{p.name}, sold {p.sales_count} times" for p in recent_products)
+    return result if Order.objects.count() else ""
+
+
+def apply_discounts():
+    orders_to_discount = Order.objects.annotate(product_count=Count('products')).filter(product_count__gt=2, is_completed=False).update(total_price=F('total_price') * 0.90)
+    return f"Discount applied to {orders_to_discount} orders."
+
+
+def complete_order():
+    order = Order.objects.filter(is_completed=False).order_by('creation_date').first()
+    if not order:
+        return ""
+    order.products.update(
+        in_stock=F('in_stock') - 1,
+        is_available=Case(
+            When(in_stock__gt=1, then=Value(True)),
+            default=False
+        )
+    )
+
+    order.is_completed = True
+    order.save()
+    return "Order has been completed!"
+
+
+
+
+if __name__ == "__main__":
+    # print(Profile.objects.get_regular_customers())
+    # print(get_profiles('the'))
+    # print(get_loyal_profiles())
+    # print(get_last_sold_products())
+    # print(get_top_products())
+    # print(apply_discounts())
+    print(complete_order())

DataBases/PythonORM/exam_prep_II/main_app/admin.py

@@ -0,0 +1,25 @@
+from django.contrib import admin
+
+from main_app.models import Profile, Product, Order
+
+
+# Register your models here.
+
+@admin.register(Profile)
+class ProfileAdmin(admin.ModelAdmin):
+    list_display = ['full_name', 'email', 'phone_number', 'is_active']
+    search_fields = ["full_name" , "email"]
+
+
+@admin.register(Product)
+class ProductAdmin(admin.ModelAdmin):
+    list_display = [ 'name', 'price', 'in_stock', 'is_available' ]
+    list_filter = [ 'is_available' ]
+    search_fields = [ 'name' ]
+
+
+@admin.register(Order)
+class OrderAdmin(admin.ModelAdmin):
+    list_display = ['profile', 'total_price', 'creation_date', 'is_completed']
+    list_filter = [ 'is_completed' ]
+    search_fields = [ 'profile__full_name' ]

DataBases/PythonORM/exam_prep_II/main_app/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+
+class MainAppConfig(AppConfig):
+    default_auto_field = 'django.db.models.BigAutoField'
+    name = 'main_app'

DataBases/PythonORM/exam_prep_II/main_app/managers.py

@@ -0,0 +1,8 @@
+from django.db import models
+from django.db.models import Count
+
+
+class ProfileManager(models.Manager):
+
+    def get_regular_customers(self):
+        return self.annotate(order_count=Count("order")).filter(order_count__gt=2).order_by('-order_count')

DataBases/PythonORM/exam_prep_II/main_app/migrations/0001_initial.py

@@ -0,0 +1,51 @@
+# Generated by Django 5.0.4 on 2024-07-29 11:56
+
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Product',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('description', models.TextField()),
+                ('price', models.DecimalField(decimal_places=2, max_digits=10, validators=[django.core.validators.MinValueValidator(0.01)])),
+                ('in_stock', models.PositiveIntegerField(validators=[django.core.validators.MinValueValidator(0)])),
+                ('is_available', models.BooleanField(default=True)),
+                ('creation_date', models.DateTimeField(auto_now_add=True)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Profile',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('full_name', models.CharField(max_length=100, validators=[django.core.validators.MinLengthValidator(2)])),
+                ('email', models.EmailField(max_length=254)),
+                ('phone_number', models.CharField(max_length=15)),
+                ('address', models.TextField()),
+                ('is_active', models.BooleanField(default=True)),
+                ('creation_date', models.DateTimeField(auto_now_add=True)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Order',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('total_price', models.DecimalField(decimal_places=2, max_digits=10, validators=[django.core.validators.MinValueValidator(0.01)])),
+                ('creation_date', models.DateTimeField(auto_now_add=True)),
+                ('is_completed', models.BooleanField(default=False)),
+                ('products', models.ManyToManyField(to='main_app.product')),
+                ('profile', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main_app.profile')),
+            ],
+        ),
+    ]

DataBases/PythonORM/exam_prep_II/main_app/migrations/0002_alter_profile_managers.py

@@ -0,0 +1,20 @@
+# Generated by Django 5.0.4 on 2024-07-29 12:25
+
+import django.db.models.manager
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AlterModelManagers(
+            name='profile',
+            managers=[
+                ('objcets', django.db.models.manager.Manager()),
+            ],
+        ),
+    ]

DataBases/PythonORM/exam_prep_II/main_app/migrations/0003_alter_profile_managers.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.0.4 on 2024-07-29 12:26
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main_app', '0002_alter_profile_managers'),
+    ]
+
+    operations = [
+        migrations.AlterModelManagers(
+            name='profile',
+            managers=[
+            ],
+        ),
+    ]

DataBases/PythonORM/exam_prep_II/main_app/models.py

@@ -0,0 +1,45 @@
+from django.core.validators import MinLengthValidator, MinValueValidator
+from django.db import models
+
+from main_app.managers import ProfileManager
+
+
+# Create your models here.
+
+class Profile(models.Model):
+    full_name = models.CharField(max_length=100, validators=[MinLengthValidator(2)])
+    email = models.EmailField()
+    phone_number = models.CharField(max_length=15)
+    address = models.TextField()
+    is_active = models.BooleanField(default=True)
+    creation_date= models.DateTimeField(auto_now_add=True)
+
+    def __str__(self):
+        return self.full_name
+
+    objects = ProfileManager()
+
+
+
+class Product(models.Model):
+    name = models.CharField(max_length=100)
+    description = models.TextField()
+    price = models.DecimalField(max_digits=10, decimal_places=2, validators=[MinValueValidator(0.01)])
+    in_stock = models.PositiveIntegerField(validators=[MinValueValidator(0)])
+    is_available = models.BooleanField(default=True)
+    creation_date = models.DateTimeField(auto_now_add=True)
+
+    def __str__(self):
+        return self.name
+
+
+
+class Order(models.Model):
+    profile = models.ForeignKey(to='Profile', on_delete=models.CASCADE)
+    products = models.ManyToManyField(to='Product')
+    total_price = models.DecimalField(max_digits=10, decimal_places=2, validators=[MinValueValidator(0.01)])
+    creation_date = models.DateTimeField(auto_now_add=True)
+    is_completed = models.BooleanField(default=False)
+
+    def __str__(self):
+        return str(self.creation_date)

DataBases/PythonORM/exam_prep_II/main_app/tests.py

@@ -0,0 +1,3 @@
+from django.test import TestCase
+
+# Create your tests here.

DataBases/PythonORM/exam_prep_II/main_app/views.py

@@ -0,0 +1,3 @@
+from django.shortcuts import render
+
+# Create your views here.

DataBases/PythonORM/exam_prep_II/manage.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python
+"""Django's command-line utility for administrative tasks."""
+import os
+import sys
+
+
+def main():
+    """Run administrative tasks."""
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()

DataBases/PythonORM/exam_prep_II/orm_skeleton/asgi.py

@@ -0,0 +1,16 @@
+"""
+ASGI config for orm_skeleton project.
+
+It exposes the ASGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/4.2/howto/deployment/asgi/
+"""
+
+import os
+
+from django.core.asgi import get_asgi_application
+
+os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'orm_skeleton.settings')
+
+application = get_asgi_application()