Enforcing Data Integrity and Business Rules

Enforcing data integrity ensures the quality of the data in the database. Two important steps when planning tables are identifying valid values for a column and deciding how to enforce the integrity of the data in the column. Data integrity falls into four categories, and is enforced in various ways.

Integrity type How enforced
Entity integrity PRIMARY KEY constraint
UNIQUE constraint
IDENTITY property
Domain integrity Domain DEFAULT definition
FOREIGN KEY constraint
CHECK constraint
Nullability
Referential integrity Domain DEFAULT definition
FOREIGN KEY constraint
CHECK constraint
Nullability
User-defined integrity All column- and table-level constraints in CREATE TABLE
Stored procedures
Triggers