1
Data abstraction is the hiding of complex, unnecessary details from database users, which is achieved through data models.
2
A data model is a collection of concepts used to describe database structure, data types, constraints, and basic operations.
3
High-level or conceptual data models use concepts close to how users perceive data, such as entities, attributes, and relationships.
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Low-level or physical data models describe how data is stored in the computer, including formats and access paths for efficient searching.
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Representational or implementation data models (relational, network, and hierarchical) use record structures and are also known as record-based data models.
6
A database schema is a blueprint or plan of the database, whereas metadata is a broader term describing data about data.
7
A database state, instance, or snapshot refers to the data stored in the database at a particular moment in time.