Showing posts with label What is UNIQUE KEY constraint?. Show all posts
Showing posts with label What is UNIQUE KEY constraint?. Show all posts

Friday 3 February 2012

What is UNIQUE KEY constraint?


What is UNIQUE KEY constraint?
A UNIQUE constraint enforces the uniqueness of the values in a set of columns, so no duplicate values are entered. The unique key constraints are used to enforce entity integrity as the primary key constraints.