Question

I have a strongly typed DataTable in my app which is generated with a couple of SQL joins. I use it to display data in a human readable way. Here’s the SQL that makes it:

SELECT     tblEvents.EventName, vwAllMembers.LASTNAME AS LastName, vwAllMembers.FIRSTNAME AS FirstName, tblEventOccurences.EventOccurenceDate, 
                  tblAttendance.AttendanceID, tblAttendanceTypes.Description AS AttendanceType, tblAttendanceTypes.Abbreviation AS AttendanceTypeAbbrv, 
                  tblAttendance.EventOccurenceID, tblAttendance.StudentID, tblAttendance.AttendanceTypeID
FROM         tblAttendance INNER JOIN
                  tblEventOccurences ON tblAttendance.EventOccurenceID = tblEventOccurences.EventOccurenceID INNER JOIN
                  tblEvents ON tblEventOccurences.EventID = tblEvents.EventID INNER JOIN
                  vwAllMembers ON vwAllMembers.Id = tblAttendance.StudentID INNER JOIN
                  tblAttendanceTypes ON tblAttendance.AttendanceTypeID = tblAttendanceTypes.AttendanceTypeID

WHERE tblAttendance.EventOccurenceID=@EventOccurenceID

I want to add a new row to that DataTable in VB. If I were inserting directly to the DB in SQL, I would just add the EventOccurenceID, StudentID, and AttendanceTypeID fields to the tblAttendance table. When I try to add only those values in VB, I get an error from my DataTable that EvenName column cannot be null (and I assume every other column as well).

Here’s my VB:

            Dim AttendanceTable As DAL.Attendance.AttendanceDataTable = AttendanceAdapter.ByEventOccurenceID(EventOccurenceID)
            Dim NewAttendanceRecord As AttendanceRow = AttendanceTable.NewAttendanceRow()
            NewAttendanceRecord.EventOccurenceID = EventOccurenceID
            NewAttendanceRecord.StudentID = StudentID
            NewAttendanceRecord.AttendanceTypeID = AttendanceTypeID

            AttendanceTable.Rows.Add(NewAttendanceRecord)

Answer 1

When you join two tables like this, its like a VIEW, not a real table. You cant add rows to a view.

Create another adapter that only returns the table you want to modify and use that to add the row.