Alomohora

Constraints are used to limit the type of data that can go into a table.

Constraints can be specified when a table is created (with the CREATE TABLE statement) or after the table is created (with the ALTER TABLE statement). We will focus on the following constraints:

• NOT NULL
• UNIQUE
• PRIMARY KEY
• FOREIGN KEY
• CHECK
• DEFAULT

The next chapters will describe each constraint in details.

Related Posts:

1. SQL DEFAULT Constraint
2. SQL CHECK Constraint
3. SQL FOREIGN KEY Constraint
4. SQL PRIMARY KEY Constraint
5. SQL UNIQUE Constraint