Database: Database is a collection of inter-related data which helps in efficient retrieval, insertion and deletion of data from database and organizes the data in the form of tables, views, schemas, reports etc. For example, university database organizes the data about students, faculty, and admin staff etc. which helps in efficient retrieval, insertion and deletion of data from it
Basically:
- database design: we'll describe an organization from the real world, like university, hospital, in terms of the data stored in the database
- data analysis: we'll answer questions about the organization by writing querys over the data in the database
If we want to use a database, we must first describe the data according to a data model.
We are using data models to describe the data that we want to keep in our databases. The data model emphasizes on what data is needed and how it should be organized instead of what operations will be performed on data. Data Model is like an architect’s building plan, which helps to build conceptual models and set a relationship between data items.
The Data Description Model is a set of concepts and rules used to model data. These concepts are used to describe the structure of the data, to specify consistency constraints(that is correctness constrains) and to describe relationships among data.
schema of the database = certain data structures are used in order to describe a collection of data stored in a database, and they constitute the schema. instances of the schema = the data items in the collection that follow the schema
Examples of DDM:
- Entity-Relationship Model
- Relational Model
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