Database Concepts & Terminology Flashcards

What is a 'view' in a relational database?

Answer: A virtual table based on the result of a stored query

A view is a virtual table defined by a SELECT query; it does not store data itself but presents data from one or more underlying tables.

In database terminology, 'cardinality' of a relationship refers to:

Answer: The numerical mapping of how many instances of one entity relate to another

Cardinality describes the numerical relationship between entity instances, such as one-to-one, one-to-many, or many-to-many.

Which normal form eliminates partial dependencies on a composite primary key?

Answer: Second Normal Form (2NF)

2NF requires that every non-key attribute is fully functionally dependent on the entire primary key, eliminating partial dependencies.

What is a 'transaction' in database terms?

Answer: A logical unit of work containing one or more SQL operations that must complete as a whole

A transaction is a unit of work that groups one or more DML operations; it either commits all changes or rolls back all changes to maintain database integrity.

The 'C' in ACID properties of a database transaction stands for:

Answer: Consistency

Consistency ensures that a transaction brings the database from one valid state to another, maintaining all defined rules and constraints.

Which type of database relationship exists when one record in Table A can relate to many records in Table B, and one record in Table B can relate to many records in Table A?

Answer: Many-to-many

A many-to-many relationship means multiple rows in one table associate with multiple rows in another, typically implemented using a junction (bridge) table.

What is 'referential integrity' in a relational database?

Answer: Guaranteeing that foreign key values always match an existing primary key value

Referential integrity is a constraint that ensures every foreign key value either matches a primary key in the referenced table or is NULL, preventing orphaned records.