A3.2.1
Describe database schemas
A database schema is the blueprint of a database. It identifies: the entities (tables) the attributes (fields) the relationships between entities the…
- A database schema is the blueprint of a database.
- It identifies:
- the entities (tables)
- the attributes (fields)
- the relationships between entities
- the constraints on the data
- Main types of schema:
- Conceptual schema
- shows the main entities and relationships
- does not include detailed attributes or data types
- used for high-level planning
- Logical schema
- shows entities, attributes, primary keys, and foreign keys
- focuses on how the database is logically structured
- Physical schema
- shows the actual implementation details
- includes data types, storage details, and constraints
- Conceptual schema