SQL try catch处理

ALTER PROC usp_AccountTransaction  
  
    @AccountNum INT,  
  
    @Amount DECIMAL  
  
AS  
  
BEGIN  
  
    BEGIN TRY --Start the Try Block..  
  
        BEGIN TRANSACTION -- Start the transaction..  
  
            UPDATE MyChecking SET Amount = Amount - @Amount  
  
                WHERE AccountNum = @AccountNum  
  
            UPDATE MySavings SET Amount = Amount + @Amount  
  
                WHERE AccountNum = @AccountNum  
  
        COMMIT TRAN -- Transaction Success!  
  
    END TRY  
  
    BEGIN CATCH  
  
        IF @@TRANCOUNT > 0  
  
            ROLLBACK TRAN --RollBack in case of Error  
  
        -- you can Raise ERROR with RAISEERROR() Statement including the details of the exception  
  
        RAISERROR(ERROR_MESSAGE(), ERROR_SEVERITY(), 1)  
  
    END CATCH  
  
END  
  
GO