Xpode.com        Click here to Print this article.

c# and SQL interview question Video :- What is the difference between unique key and primary key?

  • Unique key can have nulls .Primary key cannot have nulls.
  • In a single table we can create multiple unique keys.In a single table we can have only one primary key.
  • Unqiue key creates a non-clustered index by default.Primary Key created a clustered index by default.
  • Both unique keys and primary keys can be referenced by foreign key.

 



http://
http://

Contributed by:
Shivprasad koirala Koirala
I am a Microsoft MVP for ASP/ASP.NET and currently a CEO of a small E-learning company in India. We are very much active in making training videos , writing books and corporate trainings. Do visit my site http://www.questpond.com for .NET, C# , design pattern , WCF , Silverlight , LINQ , ASP.NET , ADO.NET , Sharepoint , UML , SQL Server training and Interview questions and answers

Resourse address on xpode.com
http://www.xpode.com/Print.aspx?Articleid=319

Click here to go on website