Updating SQL Server database with values from textboxes using stored procedure

Question

We have an aspx page which is a has a number of text boxes. We want to take the data entered into these textboxes and update our SQL Server database with them. However if any of the textboxes are left blank then we would like the data to be left as it is.

We have written the following stored procedure to carry out the update:

ALTER PROCEDURE pr_updateBooking
(
    @BookingRef INT, 
    @BoatID INT, 
    @LeadPassenger INT, 
    @StartDate Date, 
    @Duration INT, 
    @Pets INT, 
    @Children INT, 
    @Passengers INT, 
    @SpecialRequests VARCHAR(255), 
    @BalanceOutstanding NUMERIC(12, 2), 
    @Comments VARCHAR(50)
)
AS
    DECLARE @error INT

    UPDATE BookingView
    SET Balance_Outstanding = @BalanceOutstanding, 
        Comments = @Comments 
    WHERE Booking_Ref = @BookingRef

    UPDATE vBoat_Booking 
    SET BoatID = @BoatID, Lead_PassengerID = @LeadPassenger, 
        Start_Date = @StartDate, Duration_In_hours = @Duration,  
        Number_of_pets = @Pets, Number_of_children = @Children, 
        Number_of_passengers = @Passengers
    WHERE Booking_Ref = @BookingRef

    SET @error = @@error

    IF @error <> 0 
       RETURN 99
    ELSE 
       RETURN 0

Here is the C# code which will be run when the submit button is clicked on our aspx page

protected void buttonClicked(object sender, EventArgs e)
{
    string CS = ConfigurationManager.ConnectionStrings["G4StowawaysConnectionString"].ConnectionString;

    SqlConnection conn = new SqlConnection(CS);
    conn.Open();

    SqlCommand cmd2 = new SqlCommand("pr_updateBooking", conn);
    cmd2.CommandType = CommandType.StoredProcedure;

    // add our parameters to our command object  
    cmd2.Parameters.Add("@BookingRef", SqlDbType.Int).Value = BookingRef.Text;
    cmd2.Parameters.Add("@BoatID", SqlDbType.Int).Value = BoatID.Text;
    cmd2.Parameters.Add("@LeadPassenger", SqlDbType.Int).Value = LeadPassenger.Text;
    cmd2.Parameters.Add("@StartDate", SqlDbType.Date).Value = StartDate.Text;
    cmd2.Parameters.Add("@Duration", SqlDbType.Money).Value = Duration.Text;
    cmd2.Parameters.Add("@Pets", SqlDbType.Int).Value = Pets.Text;
    cmd2.Parameters.Add("@Children", SqlDbType.Int).Value = Children.Text;
    cmd2.Parameters.Add("@Passengers", SqlDbType.Int).Value = Passengers.Text;
    cmd2.Parameters.Add("@SpecialRequests", SqlDbType.VarChar, 255).Value = SpecialRequests.Text;
    cmd2.Parameters.Add("@BalanceOutstanding", SqlDbType.Int).Value = BalanceOutstanding.Text;
    cmd2.Parameters.Add("@Comments", SqlDbType.VarChar, 50).Value = Comments.Text;

    try
    {
        if (cmd2.Connection.State == ConnectionState.Closed)
        {
            cmd2.Connection.Open();
        }
        cmd2.ExecuteNonQuery();
    }
    catch (Exception)
    {
    }
    finally
    {                
        cmd2.Connection.Close();
    }
}

When we run the page there is no error message however the data is not appearing in the database!?

Answer 1

The stored procedure will not accept nulls in the parameter values, so you have somewhat of a check in place - maybe. You really need to put some code in the Catch {} block to see if the procedure is returning an error.

I don't know WHERE you want to prevent the update. The problem, as presented, should be solved in the UI. If any of the entries are empty, then don't allow a submit. Simple.

If you want the procedure to avoid performing an update, then you should set all the parameters to allow nulls. Then check for any null values before allowing the update. You could throw a user defined error or 99 (as designed). This approach would also require that you only set parameter values when the textboxes are not empty.

Answer 2

There are several issues in your application.
1. As noted in comments, use return value from int result = cmd.ExecuteNonQuery() (0 or 99). In fact it is not enough.
2. Check your table schemas to see whether or not fields of interest allow null .
3. In your stored procedure use transaction.

...
AS
--DECLARE @error INT --no need
begin transaction
begin try
UPDATE BookingView
SET Balance_Outstanding = @BalanceOutstanding, Comments = @Comments 
WHERE Booking_Ref = @BookingRef

UPDATE vBoat_Booking 
SET BoatID = @BoatID, Lead_PassengerID = @LeadPassenger, Start_Date =     @StartDate, Duration_In_hours = @Duration, Number_of_pets = @Pets,
    Number_of_children = @Children, Number_of_passengers = @Passengers
WHERE Booking_Ref = @BookingRef

commit
end try
begin catch
    DECLARE @ErrorMessage NVARCHAR(4000);
DECLARE @ErrorSeverity INT;
DECLARE @ErrorState INT;

SELECT 
    @ErrorMessage = ERROR_MESSAGE(),
    @ErrorSeverity = ERROR_SEVERITY(),
    @ErrorState = ERROR_STATE();

rollback

RAISERROR (@ErrorMessage, -- Message text.
           @ErrorSeverity, -- Severity.
           @ErrorState -- State.
           )
end catch


--SET @error = @@error

--IF @error <> 0 RETURN 99
--ELSE RETURN 0

4. In C# use catch part to see what happened.