Unique Constraint in SQL Server

In this post I would like to summarize the different articles on Unique Constraint in SQL Server. Constraints are one of the key factors in designing a table. When you are opening a bank account, bank says that you can not have more than one account in the same branch or location. This is a business rule and this can be implemented using Unique Constraints. Unique Constraints can be defined at the Column level or Table Level.