Question

I have the following T-SQL:

USE [MYDB]
GO
SET XACT_ABORT, NOCOUNT ON
GO
BEGIN TRANSACTION;
BEGIN TRY
        ALTER TABLE [dbo].[ContactRole] 
        DROP CONSTRAINT [FK_8bff7074914bc29885004c0a323] 
        GO
END TRY
BEGIN CATCH
    SELECT 
        ERROR_NUMBER() AS ErrorNumber ,ERROR_SEVERITY() AS ErrorSeverity
        ,ERROR_STATE() AS ErrorState ,ERROR_PROCEDURE() AS ErrorProcedure
        ,ERROR_LINE() AS ErrorLine ,ERROR_MESSAGE() AS ErrorMessage;

    IF @@TRANCOUNT > 0
        ROLLBACK TRANSACTION;
END CATCH

IF @@TRANCOUNT > 0
    COMMIT TRANSACTION;

Which gives me this error when parsed:

Msg 102, Level 15, State 1, Line 9
Incorrect syntax near ‘FK_8bff7074914bc29885004c0a323’.

When alone, or just within a transaction, there is no parse error.

Answer 1

Drop the GO after the ALTER TABLE ... DROP CONSTRAINT .. line

....
BEGIN TRANSACTION;
BEGIN TRY
    ALTER TABLE [dbo].[ContactRole] 
    DROP CONSTRAINT [FK_8bff7074914bc29885004c0a323] 

    COMMIT TRANSACTION;
END TRY
BEGIN CATCH
    SELECT 
        ERROR_NUMBER() AS ErrorNumber ,ERROR_SEVERITY() AS ErrorSeverity
        ,ERROR_STATE() AS ErrorState ,ERROR_PROCEDURE() AS ErrorProcedure
        ,ERROR_LINE() AS ErrorLine ,ERROR_MESSAGE() AS ErrorMessage;

    IF @@TRANCOUNT > 0
        ROLLBACK TRANSACTION;
END CATCH

GO is not a SQL keyword – it’s only understood by SQL Server Management Studio as a “batch separator”.

Also: put your COMMIT TRANSACTION statement right after the ALTER TABLE command – after all, if something does go wrong – the code execution will jump into the catch block right away, so that line is only executed if everything went OK