MS Access combo box setting a record with two primary keys - ms-access

Question

I have a database with 2 primary keys, one for a LINE NUMBER and one for PHASE of construction. The reason for this is that we have projects that may use the same Line Number but must track several Phases of the project entirely seperatly. What I have is a combo box that will drive the record information on a form. This works fine, but now when I have more than one phase it will only bring up the line's first phase and not the other 4 phases. When something other than phas one is picked it results the first phase information.
Is there a way to tie a combo box with 2 fields to select the proper record based on both fields picked?
Or maybe I need to rething the way the form is brought up... Is there a better way to do this?
Code used to select the record:
Sub SetFilter()
Dim LSQL As String
LSQL = "select * from tblLineData_Horizon"
LSQL = LSQL & " where lineno = '" & cboSelected & "'"
Form_frmHorizon_sub.RecordSource = LSQL
End Sub
Private Sub cboSelected_AfterUpdate()
'Call subroutine to set filter based on selected Line Number
SetFilter
End Sub
Private Sub Form_Open(Cancel As Integer)
'Call subroutine to set filter based on selected Line Number
SetFilter
End Sub

Answer 1

A basic idea, but you'll most likely want to tweak the behaviour a bit and have some more checks. When the form loads, you only have the ability to select LineNo. When cbxLineNo has a value in it, it enables cbxPhaseNo for selection and upon selection, it changes the RecordSource of your subform.
Private Sub cbxLineNo_AfterUpdate()
If IsNull(cbxLineNo) Then
cbxPhaseNo.Enabled = False
Else
cbxPhaseNo.Enabled = True
cbxPhaseNo.RowSource = "SELECT PhaseNo FROM tblLineData_Horizon WHERE LineNo = " & cbxLineNo & ";"
End If
End Sub
Private Sub cbxPhaseNo_AfterUpdate()
If IsNull(cbxPhaseNo) = False And IsNull(cbxLineNo) = False Then
tblLineData_Horizon_sub.Form.RecordSource = "SELECT * FROM tblLineData_Horizon WHERE LineNo = " & cbxLineNo & " AND PhaseNo = " & cbxPhaseNo & ";"
End If
End Sub
Private Sub Form_Load()
cbxLineNo.Enabled = True
cbxPhaseNo.Enabled = False
cbxLineNo.RowSource = "SELECT LineNo FROM tblLineData_Horizon GROUP BY LineNo;"
End Sub

Answer 2

You question is a little unclear, but you can create a combobox with more than one column, then your select statement would be:
where lineno = '" & cboSelected.Column(0) & "' And otherfield='"& cboSelected.Column(1)&"'"
Go to the query behind your combobox by clicking into its RowSource property and clicking the Build button (...). Once you've added the columns you need, bring up the Properties for the query and set Unique Values to Yes, so that it doesn't repeat the combinations of the fields.
You will also need to change other properties of the combobox: 'Column Count' and 'Column Widths'.