Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Chapter 12: Stored Procedures
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[ErrorProcedure],
[ErrorLine],
[ErrorMessage]
)
VALUES
(
CONVERT(sysname, CURRENT_USER),
ERROR_NUMBER(),
ERROR_SEVERITY(),
ERROR_STATE(),
ERROR_PROCEDURE(),
ERROR_LINE(),
ERROR_MESSAGE()
);
-- Pass back the ErrorLogID of the row inserted
SET @ErrorLogID = @@IDENTITY;
END TRY
BEGIN CATCH
PRINT ‘An error occurred in stored procedure uspLogError: ‘;
EXECUTE [dbo].[uspPrintError];
RETURN -1;
END CATCH
END;
Note the sections that I’ve highlighted here — these are the core to our output parameter. The first declares
the parameter as being an output parameter. The second makes the insert that utilizes the identity
value, and, finally, the SET statement captures the identity value. When the procedure exists, the value in
@ErrorLogID is passed to the calling script.
Let’s utilize our TRY/CATCH example from the tail end of the last chapter, but this time we’ll make the
call to uspLogError:
USE AdventureWorks2008;
BEGIN TRY
-- Try and create our table
CREATE TABLE OurIFTest(
Col1 int PRIMARY KEY
)
END TRY
BEGIN CATCH
-- Uh oh, something went wrong, see if it’s something
-- we know what to do with
DECLARE @MyOutputParameter int;
IF ERROR_NUMBER() = 2714 -- Object exists error, we knew this might happen
BEGIN
PRINT ‘WARNING: Skipping CREATE as table already exists’;
EXEC dbo.uspLogError @ErrorLogID = @MyOutputParameter OUTPUT;
PRINT ‘A error was logged. The Log ID for our error was ‘
+ CAST(@MyOutputParameter AS varchar);
END