Problem With IF Statement - Some Reason Not Firing Properly

Hi all, could someone be kind enough to provide me some help into why the following IF statement is not working? Basically, I am trying to find out whether a field in my database has a CONSTRAINT attached to it with a particular name... IF it does have one then drop it and re-create it ELSE simply create one.

I have used SELECT * FROM SYSOBJECTS to find whether it exists which according to the results it does EXIST, however my IF statement is not detecting it and I get an error which states:
Msg 1781, Level 16, State 1, Line 30Column already has a DEFAULT bound to it.Msg 1750, Level 16, State 0, Line 30Could not create constraint. See previous errors.

However, surely my IF statement is suppose to be handling this problem and therefore if it does EXIST THEN it should ideally drop the CONSTRAINT and then re-create it but this is not the case... instead the ELSE is always being triggered. After using SYSOBJECTS I copied it directly from the results view into my SQL but still for some reason if my constraint does exist it jumps to the ELSE.






Code SnippetIF EXISTS (SELECT * FROM SYSOBJECTS WHERE NAME = '[DF_TBL_SyncTable_OB-DEVUK]')
BEGIN
ALTER TABLE TBL_SyncTable DROP CONSTRAINT [DF_TBL_SyncTable_OB-DEVUK]
ALTER TABLE TBL_SyncTable ADD CONSTRAINT [DF_TBL_SyncTable_OB-DEVUK] DEFAULT 2 FOR [OB-DEVUK]
ALTER TABLE TBL_SyncTable ADD [OB-DEV6] TINYINT DEFAULT 2
END
ELSE BEGIN ALTER TABLE TBL_SyncTable ADD CONSTRAINT [DF_TBL_SyncTable_OB-DEVUK] DEFAULT 2 FOR [OB-DEVUK]
ALTER TABLE TBL_SyncTable ADD [OB-DEV6] TINYINT DEFAULT 2
END


Thanks for replies + suggestions + comments

Regards, Onam.