Create Exam_Preparation_I.sql

DataBases/PostgreSQL/Exam_Preparation_I.sql

@@ -0,0 +1,284 @@
+-- Task 1
+
+-- CREATE DATABASE zoo_db;
+
+CREATE TABLE owners(
+    id INT GENERATED ALWAYS AS IDENTITY UNIQUE PRIMARY KEY,
+    name VARCHAR(50) NOT NULL ,
+    phone_number VARCHAR(15) NOT NULL ,
+    address VARCHAR(50)
+);
+
+CREATE TABLE animal_types(
+    id INT GENERATED ALWAYS AS IDENTITY UNIQUE PRIMARY KEY,
+    animal_type VARCHAR(50) NOT NULL
+);
+
+CREATE TABLE cages(
+    id INT GENERATED ALWAYS AS IDENTITY UNIQUE PRIMARY KEY,
+    animal_type_id INT NOT NULL REFERENCES animal_types
+                  ON UPDATE CASCADE
+                  ON DELETE CASCADE
+);
+
+CREATE TABLE animals(
+    id INT GENERATED ALWAYS AS IDENTITY UNIQUE PRIMARY KEY,
+    name VARCHAR(30) NOT NULL,
+    birthdate DATE NOT NULL,
+    owner_id INT REFERENCES owners
+                    ON DELETE CASCADE
+                    ON UPDATE CASCADE,
+    animal_type_id INT NOT NULL REFERENCES animal_types
+                    ON UPDATE CASCADE
+                    ON DELETE CASCADE
+);
+
+CREATE TABLE volunteers_departments(
+    id INT GENERATED ALWAYS AS IDENTITY UNIQUE PRIMARY KEY,
+    department_name VARCHAR(30) NOT NULL
+);
+
+CREATE TABLE volunteers(
+    id INT GENERATED ALWAYS AS IDENTITY UNIQUE PRIMARY KEY,
+    name VARCHAR(50) NOT NULL,
+    phone_number VARCHAR(15) NOT NULL,
+    address VARCHAR(50),
+    animal_id INT REFERENCES animals
+                       ON DELETE CASCADE
+                       ON UPDATE CASCADE,
+    department_id INT NOT NULL REFERENCES volunteers_departments
+                       ON DELETE CASCADE
+                       ON UPDATE CASCADE
+);
+
+CREATE TABLE animals_cages(
+    cage_id INT NOT NULL REFERENCES cages
+                          ON UPDATE CASCADE
+                          ON DELETE CASCADE ,
+    animal_id INT NOT NULL REFERENCES animals
+                          ON DELETE CASCADE
+                          ON UPDATE CASCADE--,
+--     CONSTRAINT pk_animals_cages PRIMARY KEY (cage_id,animal_id)
+);
+
+-- Task 2
+
+INSERT INTO
+    volunteers(
+    name,
+    phone_number,
+    address,
+    animal_id,
+    department_id
+)
+VALUES
+    ('Anita Kostova',	'0896365412',	'Sofia, 5 Rosa str.',	15,	1),
+    ('Dimitur Stoev',	'0877564223',	NULL,	42,	4),
+    ('Kalina Evtimova',	'0896321112',	'Silistra, 21 Breza str.',	9,	7),
+    ('Stoyan Tomov',	'0898564100',	'Montana, 1 Bor str.',	18,	8),
+    ('Boryana Mileva',	'0888112233',	NULL,	31,	5);
+
+INSERT INTO
+    animals(
+            name,
+            birthdate,
+            owner_id,
+            animal_type_id
+)
+VALUES
+    ('Giraffe',	'2018-09-21',	21,	1),
+    ('Harpy Eagle',	'2015-04-17',	15,	3),
+    ('Hamadryas Baboon',	'2017-11-02',	NULL,	1),
+    ('Tuatara',	'2021-06-30',	2,	4);
+
+-- Task 3
+
+UPDATE
+    animals
+SET
+    owner_id = (SELECT id FROM owners WHERE name = 'Kaloqn Stoqnov')
+WHERE
+    owner_id IS NULL;
+
+-- Task 4
+
+DELETE FROM
+    volunteers_departments
+WHERE
+    department_name = 'Education program assistant';
+
+-- Task 5
+
+SELECT
+    name,
+    phone_number,
+    address,
+    animal_id,
+    department_id
+FROM
+    volunteers
+ORDER BY
+        name,
+        animal_id,
+        department_id;
+
+-- Task 6
+
+SELECT
+    name,
+    animal_type,
+    TO_CHAR(birthdate,'DD.MM.YYYY') AS birthdate
+FROM
+    animals AS a
+JOIN
+    animal_types AS at
+ON
+    at.id = a.animal_type_id
+ORDER BY
+    a.name;
+
+-- Task 7
+
+SELECT
+    o.name AS owner,
+    COUNT(a) AS count_of_animals
+FROM
+    owners AS o
+JOIN
+    animals AS a
+ON
+    a.owner_id = o.id
+GROUP BY
+    o.name
+ORDER BY
+    count_of_animals DESC,
+    o.name
+LIMIT 5;
+
+-- Task 8
+
+SELECT
+    CONCAT(o.name,' - ',a.name) AS "owners - animals",
+    phone_number,
+    cage_id
+FROM
+    owners AS o
+JOIN
+    animals AS a
+ON
+    o.id = a.owner_id
+JOIN
+    animals_cages AS ag
+ON
+    ag.animal_id = a.id
+JOIN
+    cages AS cg
+ON
+    cg.id = ag.cage_id
+JOIN
+    animal_types AS at
+ON
+    at.id = a.animal_type_id
+WHERE
+    at.animal_type = 'Mammals'
+ORDER BY
+    o.name,
+    a.name DESC;
+
+-- Task 9
+
+SELECT
+    v.name AS volunteers,
+    phone_number,
+    LTRIM(address, 'Sofia, ') AS address
+FROM
+    volunteers AS v
+JOIN
+    volunteers_departments AS vd
+ON
+    vd.id = v.department_id
+WHERE
+    address ILIKE '%Sofia%'
+        AND
+    vd.department_name = 'Education program assistant'
+ORDER BY
+    v.name;
+
+-- Task 10
+
+SELECT
+    a.name AS animal,
+    EXTRACT(YEAR FROM a.birthdate) AS birth_year,
+    animal_type
+FROM
+    animals AS a
+JOIN
+    animal_types AS at
+ON
+    at.id = a.animal_type_id
+WHERE
+    a.owner_id IS NULL
+        AND
+    '01/01/2022'::DATE - INTERVAL '5 years' < a.birthdate
+        AND
+    at.animal_type <> 'Birds'
+ORDER BY
+    a.name;
+
+-- Task 11
+
+CREATE OR REPLACE FUNCTION fn_get_volunteers_count_from_department(
+    searched_volunteers_department VARCHAR(30)
+)
+RETURNS INT
+AS
+    $$
+        BEGIN
+                RETURN
+                (SELECT
+                    COUNT(v)
+                FROM
+                    volunteers_departments AS vd
+                JOIN
+                    volunteers AS v
+                ON
+                    v.department_id = vd.id
+                WHERE vd.department_name = searched_volunteers_department);
+        END;
+    $$
+LANGUAGE plpgsql;
+
+-- SELECT fn_get_volunteers_count_from_department('Zoo events')
+
+-- Task 12
+
+CREATE OR REPLACE PROCEDURE sp_animals_with_owners_or_not(
+    animal_name VARCHAR(30),
+    OUT owner_name VARCHAR(50)
+)
+AS
+    $$
+--         DECLARE
+--             owner_name VARCHAR(50);
+        BEGIN
+            SELECT
+                COALESCE(o.name,'For adoption')
+            INTO
+                owner_name
+            FROM
+                animals AS a
+            LEFT JOIN
+                owners AS o
+            ON
+                a.owner_id = o.id
+            WHERE
+                a.name = animal_name;
+            RAISE NOTICE '%',owner_name;
+        END;
+    $$
+LANGUAGE plpgsql;
+
+
+-- CALL sp_animals_with_owners_or_not('Pumpkinseed Sunfish','');
+-- CALL sp_animals_with_owners_or_not('Hippo','');
+-- CALL sp_animals_with_owners_or_not('Brown bear', '');