http://www.sqlservercentral.com/blogs/katie-and-emil/2012/07/24/sql-unique-constraint/ Printed 2016/12/06 02:00AM
SQL Unique Constraint
2012/07/24In this blog psot we show how to restrict users from entering duplicated data by using SQL UNIQUE Constraint. In our examples we will use unique constraint on one field and we will use Email Address and one multiple fields and we will use First Name, Surname and Birth Date. This article has been written to support our SQL Tutorial and Exam Guide 70-461 Querying SQL Server 2012.