Primary Key vs Uniqueindentifier vs Unique Key in SQL Server

Published on Monday, October 4, 2010

- Primary key – Only one Identity column – Can't be null

- Identity – Automatic value – Only one Identity column – Can't be null – Can exist in addition of primary key, GUID-auto columns

- Uniqueindentifier – Can be multiple – Can be null

- Uniqueindentifier - rowguid – Auto generated – Only one Identity column – Can be null – Can exist in addition of primary key, Identity columns

- Unique Key

-- Can be null
-- Can be multiple

From .NETTer Characters