Stored Procedure Transaction

Question

I have never used a Transaction, Commit and Rollback before and now I need to use one. I have checked around online, etc for examples to make sure that I am in fact using this correctly but I am still not sure if I have coded this correct. I am hoping someone can review and advise me if this seems correct.

Basically I have 2 databases for an application. One is an archive - meaning data that is no longer going to be manipulated by the users will be moved to this DB. But in the event they ever need it, I will move the needed data back to the main database for use. My stored proc is below:

CREATE PROCEDURE [dbo].[spReopenClosed] 
(
    @Return_Message VARCHAR(1024) = ''  OUT,        
    @IID        uniqueidentifier,
    @OpenDate   smalldatetime,
    @ReopenedBy uniqueidentifier
)
AS
BEGIN
    SET NOCOUNT ON;

/******************************
*  Variable Declarations
*******************************/
    DECLARE     @ErrorCode  int  



/******************************
*  Initialize Variables
*******************************/

    SELECT @ErrorCode = @@ERROR

    IF @ErrorCode = 0

    BEGIN TRANSACTION
        /****************************************************************************
        * Step 1
        * Copy the Closed from the Archive
        ****************************************************************************/
        INSERT INTO OPS.dbo.SM_T_In
        SELECT          
        FROM OPS_ARCHIVE.Archive.SM_T_In    W
        WHERE W.GUID = @IID
            AND W.OpenDate = @OpenDate


        IF @ErrorCode <> 0
            BEGIN
                -- Rollback the Transaction
                ROLLBACK

                RAISERROR ('Error in Copying from the archive', 16, 1)
                RETURN
            END


        /****************************************************************************
        * Step 2
        * copy the notes
        ****************************************************************************/
        INSERT INTO OPS.dbo.SM_T_Notes
        SELECT 
        FROM OPS_ARCHIVE.Archive.SM_T_Notes W
        WHERE W.GUID = @IID

        IF @ErrorCode <> 0
            BEGIN
                -- Rollback the Transaction
                ROLLBACK

                RAISERROR ('Error in copying the notes', 16, 1)
                RETURN
            END

        /****************************************************************************
        * Step 3
        * Delete the from the Archive - this will also delete the notes
        ****************************************************************************/
        DELETE
        FROM OPS_ARCHIVE.Archive.SM_T_In
        WHERE OPS_ARCHIVE.Archive.SM_T_In.GUID = @IID

        IF @ErrorCode <> 0
            BEGIN
                -- Rollback the Transaction
                ROLLBACK

                RAISERROR ('Error in deleting the items from the Archive', 16, 1)
                RETURN
            END

        COMMIT

        BEGIN
            SELECT  @ErrorCode  = @@ERROR

            IF @ErrorCode = 0
                    SELECT  @Return_Message = 'All data was moved over'
        END



/*************************************
*  Get the Error Message for @@Error
*************************************/
    IF @ErrorCode <> 0
    BEGIN
        SELECT  @Return_Message = [Description]     -- Return the SQL Server error
          FROM  master.dbo.SYSMESSAGES
         WHERE  error = @ErrorCode
    END

/*************************************
*  Return from the Stored Procedure
*************************************/
    RETURN @ErrorCode                               -- =0 if success,  <>0 if failure
END

I have two inserts that move the data from 2 tables from the Archive database. If those inserts are successful, then I will delete the data from the Archive DB. I would appreciate any feedback on this, I need to make sure that I am doing this properly.

Thanks

Answer 1

Oh well i rewrite quickly your SP using the concept TRY CATCH and the TRANSACTION as you requested but i didnt check it.

This code will work in SQL 2005/2008

Let me know if this feedback can be useful for you

CREATE PROCEDURE [dbo].[spReopenClosed] 
(
    @Return_Message VARCHAR(1024) = ''  OUT,        
    @IID        uniqueidentifier,
    @OpenDate   smalldatetime,
    @ReopenedBy uniqueidentifier
)
AS

    SET NOCOUNT ON;

/******************************
*  Variable Declarations
*******************************/
    DECLARE     @ErrorCode  int  
    DECLARE     @ErrorStep  varchar(200)

/******************************
*  Initialize Variables
*******************************/

    SELECT @ErrorCode = @@ERROR

BEGIN TRY

    BEGIN TRAN
        /****************************************************************************
        * Step 1
        * Copy the Closed from the Archive
        ****************************************************************************/

        SELECT @ErrorStep = 'Error in Copying from the archive';

        INSERT INTO OPS.dbo.SM_T_In
        SELECT *         
        FROM OPS_ARCHIVE.Archive.SM_T_In
        WHERE GUID = @IID
            AND W.OpenDate = @OpenDate


        /****************************************************************************
        * Step 2
        * copy the notes
        ****************************************************************************/

        SELECT @ErrorStep = 'Error in copying the notes'

        INSERT INTO OPS.dbo.SM_T_Notes
        SELECT *
        FROM OPS_ARCHIVE.Archive.SM_T_Notes
        WHERE GUID = @IID

        /****************************************************************************
        * Step 3
        * Delete the from the Archive - this will also delete the notes
        ****************************************************************************/

        SELECT @ErrorStep = 'Error in deleting the items from the Archive'

        DELETE
        FROM OPS_ARCHIVE.Archive.SM_T_In
        WHERE OPS_ARCHIVE.Archive.SM_T_In.GUID = @IID

    COMMIT TRAN

    SELECT  @ErrorCode  = 0, @Return_Message = 'All data was moved over'

    /*************************************
    *  Return from the Stored Procedure
    *************************************/
    RETURN @ErrorCode                               -- =0 if success,  <>0 if failure

END TRY

BEGIN CATCH
    /*************************************
    *  Get the Error Message for @@Error
    *************************************/
    IF @@TRANCOUNT > 0 ROLLBACK

    SELECT @ErrorCode = ERROR_NUMBER()
        , @Return_Message = @ErrorStep + ' '
        + cast(ERROR_NUMBER() as varchar(20)) + ' line: '
        + cast(ERROR_LINE() as varchar(20)) + ' ' 
        + ERROR_MESSAGE() + ' > ' 
        + ERROR_PROCEDURE()

    /*************************************
    *  Return from the Stored Procedure
    *************************************/
    RETURN @ErrorCode                               -- =0 if success,  <>0 if failure

END CATCH

Answer 2

First, databases are fairly reliable. And if they fail, you have a bigger problem than handling individual transactions. So my feedback would be that you have too much error checking for a simple transaction. A failing insert is such an unusual event that you normally wouldn't write code to handle it.

Second, this code won't actually "catch" errors:

IF @ErrorCode <> 0

An error in the SQL statement will abort the stored procedure and return to the client. You'd have to try ... catch to actually handle an error in a stored procedure.

Third, I try to avoid raiserr. It can do unexpected things both on the server and the client side. Instead, consider using an output parameter to return error information to the client program.