Tag Archives: SQL Primary Keys and Foreign Keys

Sql server Constraints – Primary Key, Foreign Key, Unique Key, Not Null, Check Constraints

By | August 19, 2009

A constraint is a property that is assigned to a column or a group of columns to prevent incorrect or corrupt data from entering into the tables. These constraints ensure the accuracy and reliability of the data into the tables. Let’s suppose we have two tables Employee and Department whose description is given below:- CREATE… Read More »