Database Integrity and Keys

Question 1

Entity Integrity

Answer 1

Entity Integrity: Ensures that each row in a relational database table is uniquely identified by a primary key, and no attribute in that primary key contains a null value.

Question 2

Domain Integrity

Answer 2

Domain Integrity: Enforces valid entries for a given column by defining a domain, which is the set of permissible values for that column.

Question 3

Referential Integrity

Answer 3

Referential Integrity: Ensures the consistency between tables by enforcing relationships between tables through foreign keys. It guarantees that foreign key values refer to existing primary key values.

Question 4

Candidate Key

Answer 4

Candidate Key: A candidate key is a set of one or more attributes that can uniquely identify a tuple in a relation. It is a candidate for becoming a primary key.