Handling of different return code correspondingly in a stored procedure

  • Thread starter Thread starter Fir5tSight
  • Start date Start date
F

Fir5tSight

Hi All,

I have a C#.NET code as follows:

private void ScanInput_KeyPress(object sender,
System.Windows.Forms.KeyPressEventArgs e)
{
try
{
Row lRow = this.Connection.InsertScannedFile(ID);



}
catch (Exception /*lException*/)
{
textMessage.Text = "The ID value cannot be found in the system.";
}
}

void InsertScannedFile (int id)
{
this.ExecuteStoredProcedure(lReturn,


Constants.StoredProcedures.SPInsertScannedFile,
new SqlParameter("@ID",id));

return lReturn.SPInsertScannedFile[0];
}

// The stored procedure is like the follows:

CREATE PROCEDURE SPInsertScannedFile
@ID DTObjectID,

AS

IF EXISTS
(
SELECT
DistributionID
FROM
table1
WHERE
DistributionID = @ID

)
BEGIN
RAISERROR ('The file is already in the system!',16,1)
RETURN 1
END


IF NOT EXISTS
(
SELECT
FileID
FROM
table2
WHERE
FileID = @ID

)
BEGIN
RAISERROR ('The file is already scanned.',16,1)
RETURN 2
END


-- insert a new record
INSERT INTO
table2
(
ID,
Time_recorde_inserted
)
SELECT
@ID,
getdate()



-- return the details
SELECT
-- some field names
FROM
table1 INNER JOIN table2 -- etc.
WHERE
table1.DistributionID = @ID


RETURN 0
GO

--------------------------------------------------------------------------------
Could anyone advise me how to handle different return code (1 or 2)
differently from the stored procedure in the C# code? For instance, if
1 is returned, set textMessage.Text as "The file is already in the
system!" However, if 2 is returnd, set textMessage.Text as "The file is
already scanned.".

Thanks!
 
Fir5tSight,

Normally you would use commandObject.ExecuteScalar. Since you have a SELECT
returning - which is a recordset/resultset if you will - you will need to
navigate thru the results. If you will need to determine whether the result
set you're reading has more than one column. If it has just one column, that
it is your return result. Otherwise, is the resultset your are returning to
your interface. There is a property called FieldCount which would answer
that question for you.

Hope it helps.

Robson
 
Hi Robson,

Thanks for answering my question!

I want to know how to pass the specific error raised in the stored
procedure to the C# calling method. For instance, how to get the C#
code to display the message, 'The file is already in the system!', when
the first check in the stored procedure fails. For another instance,
how to get the C# code to display the message, 'The file is already
scanned.', when the second check in the stored procedure fails.

I use a return code of 1 and 2 to distinguish these two different
errors raised in the stored procedure. However, I wish to know how to
get this info in the calling C# code.

-Emily
 
Hi All,

I have a C#.NET code as follows:

private void ScanInput_KeyPress(object sender,
System.Windows.Forms.KeyPressEventArgs e)
{
try
{
Row lRow = this.Connection.InsertScannedFile(ID);

}
catch (Exception /*lException*/)
{
textMessage.Text = "The ID value cannot be found in the system.";
}
}

void InsertScannedFile (int id)
{
this.ExecuteStoredProcedure(lReturn,

Constants.StoredProcedures.SPInsertScannedFile,
new SqlParameter("@ID",id));

return lReturn.SPInsertScannedFile[0];
}

// The stored procedure is like the follows:

CREATE PROCEDURE SPInsertScannedFile
@ID DTObjectID,

AS

IF EXISTS
(
SELECT
DistributionID
FROM
table1
WHERE
DistributionID = @ID

)
BEGIN
RAISERROR ('The file is already in the system!',16,1)
RETURN 1
END

IF NOT EXISTS
(
SELECT
FileID
FROM
table2
WHERE
FileID = @ID

)
BEGIN
RAISERROR ('The file is already scanned.',16,1)
RETURN 2
END

-- insert a new record
INSERT INTO
table2
(
ID,
Time_recorde_inserted
)
SELECT
@ID,
getdate()

-- return the details
SELECT
-- some field names
FROM
table1 INNER JOIN table2 -- etc.
WHERE
table1.DistributionID = @ID

RETURN 0
GO

--------------------------------------------------------------------------------
Could anyone advise me how to handle different return code (1 or 2)
differently from the stored procedure in the C# code? For instance, if
1 is returned, set textMessage.Text as "The file is already in the
system!" However, if 2 is returnd, set textMessage.Text as "The file is
already scanned.".

Thanks!
Click to expand...

Personally i'd eschew the return values approach and rewrite the procedure
to use output parameters instead. For one thing this would make extending
the logic easier as well as keeping the application logic in the
application.

So after executing the query i'd check the return value and then based on
that throw the appropriate exception within the .NET application
 
You shouldn't be sending back error message text from the stored procedure -
send back a numeric return code, put a corresponding enumeration in your
application code and throw an exception if appropriate. As was mentioned in
another reply, use output parameters instead of "return codes". In general,
you should always avoid putting application logic in the data layer.
Further, you should avoid passing back string values to indicate what are
really application errors. In other words, nothing "went wrong" in the data
layer; rather you received a result that indicates something "went wrong" in
the application.
 
Hi Karch,

Thanks for the advice! I'll use a parameter to return the error code
from the stored procedure, and then handle the exception based on the
error code.

I won't return any textual string from the stored procedure.

-Emily
 
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