sql存储过程中的多个更新

Question

What is the best way to handle return values when using multiple update statements in a stored procedure.

I am using this stored procedure in a data adapter and am trying to get the update result total.

I'm using SQL Server 2008 and .NET 4.5

For example:

CREATE PROCEDURE [dbo].[usrsp_MessageConversation_delete]
(
    @fromMbrID int,
    @toMbrID int
)
AS
BEGIN
SET NOCOUNT OFF;
UPDATE mbr_Messages
SET  fromDeleted = 1
WHERE (fromMbrID = @fromMbrID) AND (toMbrID = @toMbrID)

UPDATE mbr_Messages
    SET toDeleted = 1
WHERE (fromMbrID = @toMbrID) AND (toMbrID = @fromMbrID)

//RETURN TOTAL NUMBER OF UPDATED RECORDS
    EG: RETURN  @@ROWCOUNT ??

END

I want to return the total number of updated records or 0 if non were updated.

Do I need to add any other error handling - if so any suggestions?

UPDATE: I ended up going with this:

BEGIN

SET NOCOUNT ON;

DECLARE @rowCounter INT;

BEGIN TRY 

    UPDATE 
        mbr_Messages
    SET 
        fromDeleted = 1
    WHERE 
        (fromMbrID = @fromMbrID) AND (toMbrID = @toMbrID) AND (fromDeleted = 0);

    SET @rowCounter = @@ROWCOUNT;

    UPDATE 
        mbr_Messages
    SET 
        toDeleted = 1
    WHERE 
        (fromMbrID = @toMbrID) AND (toMbrID = @fromMbrID) AND (toDeleted = 0);

    SET @rowCounter = @rowCounter + @@ROWCOUNT;

END TRY
BEGIN CATCH
    PRINT 'Update failed';
END CATCH 

RETURN @rowCounter

END

Answer 1

You want to do something like below:

CREATE PROCEDURE [dbo].[usrsp_MessageConversation_delete]
(
    @fromMbrID int,
    @toMbrID int
)
AS
BEGIN
SET NOCOUNT OFF;
    DECLARE @RowCount1 INTEGER
    DECLARE @RowCount2 INTEGER
    DECLARE @TotalRows INTEGER

UPDATE mbr_Messages
SET  fromDeleted = 1
WHERE (fromMbrID = @fromMbrID) AND (toMbrID = @toMbrID)

SET @RowCount1=@@RowCount

UPDATE mbr_Messages
    SET toDeleted = 1
WHERE (fromMbrID = @toMbrID) AND (toMbrID = @fromMbrID)

SET @RowCount2=@@RowCount

SET @TotalRows = @RowCount1 + @RowCount2

--RETURN TOTAL NUMBER OF UPDATED RECORDS
  RETURN  @TotalRows

END

You need to assign @@RowCount to some variable as it gets reset once you use it.

Edit:

Also add error handling code: Try..Catch and Transactions.

Answer 2

If your stored procedure is short, I not really suggest to use any error handling.

But here is one example for error handling

IF @@ERROR <> 0 
BEGIN
   --your statement 
   return 12345; -- to mark your error location 
END

More information about @@Error

Answer 3

Use a transaction, near the start of your procedure use this command to start a transaction:

BEGIN TRANSACTION

Check for errors in your script (can be used multiple times)

IF @@ERROR <> 0
BEGIN
    ROLLBACK
    RAISERROR ('error updating something', 16,1)
    RETURN
END

then at the end of your script commit the transaction

COMMIT

Answer 4

you can use OUTPUT clause to count updated/inserted or deleted records

DECLARE @MyTableVar table (
flagdeleted bit NOT NULL);

UPDATE mbr_Messages
SET fromDeleted = 1
OUTPUT INSERTED.fromDeleted INTO @MyTableVar 
WHERE (fromMbrID = @fromMbrID) AND (toMbrID = @toMbrID)

UPDATE mbr_Messages
SET toDeleted = 1
OUTPUT INSERTED.toDeleted INTO @MyTableVar 
WHERE (fromMbrID = @toMbrID) AND (toMbrID = @fromMbrID)

SELECT COUNT(*) FROM @MyTableVar //here is the number of updated records

Answer 5

CREATE PROCEDURE [dbo].[usrsp_MessageConversation_delete]
(
    @fromMbrID int,
    @toMbrID int
)
AS
DECLARE 
@SQL1 VARCHAR(800),
@SQL2 VARCHAR(800)
BEGIN
SET NOCOUNT OFF;

SET @SQL1 ='
UPDATE mbr_Messages
SET  fromDeleted = ''1''
WHERE (fromMbrID = '+@fromMbrID+') AND (toMbrID = '+@toMbrID+')'
PRINT @SQL1

SET @SQL2 ='
UPDATE mbr_Messages
    SET toDeleted = ''1''
WHERE (fromMbrID = '+@toMbrID+') AND (toMbrID = '+@fromMbrID+')'

PRINT @sql2


EXEC(@SQL1)

EXEC(@SQL2)
END

Answer 6

Try this

BEGIN TRY
BEGIN TRAN
 -- Your code here
COMMIT TRAN
END TRY
BEGIN CATCH
    ROLLBACK TRAN
END CATCH

This will return number of rows affected (updated row). 0 (affected row will be 0 after roll back) if error.

Answer 7

The return value for SqlCommand.ExecuteNonQuery will give you the number of rows affected by your query. In your case it will add the row counts of the two UPDATE statements in your proc. There is no need to add a RETURN statement to your stored procedure.

SqlCommand command;
...
int numberOfRecords = command.ExecuteNonQuery();