Identify Record Not Found

[DonnaF]

I have an application where I am asking the user to enter a signon and password. Then the customer file is read to see if they are valid. I do not need to retrieve any of the data - just verify that the record is on the database table. A couple of questions - How did I determine if the no records were found, after doing the select (see the code below)? Do I need to fill a dataset, and compare the fields (signon and password) to what was passed to the select statement? How do I access the dataset fields to do the compare? The only experience I have is with datasets is filling datagrids.

 

DataAdapter1.SelectCommand.CommandText = _

"SELECT CustomerID, UserPassword FROM Customers " & _

"WHERE CustomerID = 'mcustID' & UserPassword = 'mPassword'"

Try

DataAdapter1.SelectCommand.ExecuteNonQuery()

 

Catch exceptionparameter As Exception

MessageBox.Show(exceptionparameter.Message)

End Try

 

I'm never hitting the Catch statement, no matter if the signon/password is valid or not.

 

Thanks, Donna

[LostProgrammer]

There isn't an error or an exception being thrown. You are returning an empty dataset. Another way to try is using a datareader and then testing the rdr.Read condition. If it is false then there are no matching records.

[kleptos]

Here is a small example i used a while back when learning ADO.NET programming. Its written in C#, but the basics are there. The part you may be interested in is this:

if(datareader.HasRows)
{
   // User Exists
}
else
{
   // No User Exists
}

 

This may help you out, i hope it helps even a little.

firstexample.zip