CODEWITHSUNDEEP
sql-server-2005unique-constraint
User
User

Reputation: 3274

Unique Key Violation in SQL Server - Is it safe to assume Error 2627?

I need to catch violation of UNIQUE constraints in a special way by a C# application I am developing. Is it safe to assume that Error 2627 will always correspond to a violation of this kind, so that I can use 

if (ThisSqlException.Number == 2627)
{
    // Handle unique constraint violation.
}
else
{
    // Handle the remaing errors.
}

?

Upvotes: 81

Views: 87440

Answers (3)

Damien_The_Unbeliever
Damien_The_Unbeliever

Reputation: 239814

Within an approximation, yes.

If you search the MS error and events site for SQL Server, error 2627, you should hopefully reach this page1, which indicates that the message will always concern a duplicate key violation (note which parts are parameterized, and which not):

Violation of %ls constraint '%.*ls'. Cannot insert duplicate key in object '%.*ls'.

1As @2020-06-18, Database engine errors and events would be the correct page to go to

Upvotes: 5

jhilden
jhilden

Reputation: 12449

Here is a handy extension method I wrote to find these:

    public static bool IsUniqueKeyViolation(this SqlException ex)
    {
        return ex.Errors.Cast<SqlError>().Any(e => e.Class == 14 && (e.Number == 2601 || e.Number == 2627 ));
    }

Upvotes: 24

gbn
gbn

Reputation: 432639

2627 is unique constraint (includes primary key), 2601 is unique index

SELECT * FROM sys.messages
WHERE text like '%duplicate%' and text like '%key%' and language_id = 1033

Upvotes: 136

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