How to check if a Constraint exists in Sql server?

Question

I have this sql:

ALTER TABLE dbo.ChannelPlayerSkins
    DROP CONSTRAINT FK_ChannelPlayerSkins_Channels

but apparently, on some other databa

Answer 1

You can use the one above with one caveat:

IF EXISTS(
    SELECT 1 FROM sys.foreign_keys 
    WHERE parent_object_id = OBJECT_ID(N'dbo.TableName') 
        AND name = 'CONSTRAINTNAME'
)
BEGIN 
    ALTER TABLE TableName DROP CONSTRAINT CONSTRAINTNAME 
END 

Need to use the name = [Constraint name] since a table may have multiple foreign keys and still not have the foreign key being checked for