6.   Explain what entity and relational integrity are, and what rules the RDMS maintains in enforcing them

 

Entity Integrity

All Entries MUST be unique (No two records can have the same Primary Key

Primary Keys can NOT be Null

Relational Integrity

Foreign Keys MUST have a corresponding field in the Related Table (or be NULL)

The Primary key in the table referred to Can NOT be deleted if a foreign key refers to it