Unique constraint in Entity Framework [duplicate]

This quest开发者_JAVA百科ion already has answers here: Unique keys in Entity Framework 4 (5 answers) Closed 9 years ago.

How can one set some attribute in Entity (Entity Framework) to be unique? One possibility would be to make it primary key but that's not what I want.

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Entity framework doesn't support unique keys so the only way is to set the unique constraint / index in the database. It will not ensure uniqueness in the application when you try to insert / update records but the exception will be fired if you try to save non unique value to the database.

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http://blogs.msdn.com/b/efdesign/archive/2011/03/09/unique-constraints-in-the-entity-framework.aspx

also see Unique keys in Entity Framework 4