Database Concepts and Architecture

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What is a database?

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A database is a collection of related data that represents some aspect of the real world.

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What is a Database Management System (DBMS)?

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A DBMS is a collection of programs that enables users to create and maintain a database.

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What are the main characteristics of the database approach?

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1. Self-describing nature of a database system 2. Insulation between programs and data 3. Support of multiple views of the data 4. Sharing of data and multiuser transaction processing.

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What is meta-data in a database?

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Meta-data is the data that describes the structure of the database, including the types and constraints of the data.

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What is the purpose of data abstraction in databases?

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Data abstraction suppresses details of data organization and storage, highlighting essential features for better understanding.

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What are the three levels of the three-schema architecture?

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1. Internal level: describes physical storage structure. 2. Conceptual level: describes the structure of the whole database. 3. External level: describes user views.

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What is an entity in the Entity-Relationship (ER) model?

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An entity is a thing in the real world with an independent existence, such as a person or a project.

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What is a relationship type in the ER model?

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A relationship type defines a set of associations among entities from different entity types.

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What is a primary key in a relational database?

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A primary key is an attribute or set of attributes that uniquely identifies each tuple in a relation.

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What is referential integrity in databases?

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Referential integrity ensures that a foreign key in one relation must refer to an existing tuple in another relation.