There's really nothing to post. Based on the DB I uploaded, the issue was not being able to add records to the query. So I stopped adding records to the query and instead just added records to the "Master" table from my form, looking up the "Thing" values in code. I'll post my actual code here, though of course it goes with my full DB and not the example I uploaded.
Code:
Public Sub AddItemWithMFG(MFG As String, ModelNumber As String, HasUniqueID As Boolean, IsPhysical As Boolean)
'Create my database as a variable
Dim dbInventory As DAO.Database
Set dbInventory = CurrentDb
'Create my Items table as a variable
Dim rstItems As DAO.Recordset
Set rstItems = dbInventory.OpenRecordset("Items")
'Add a new item to my Items table
rstItems.AddNew
'Look up ID associated with MFG value. This is what I was trying to use the query for.
Dim MFGID As Integer
MFGID = DLookup("ID", "MFGList", "MFG='" & MFG & "'")
rstItems("Manufacturer").Value = MFGID
'Add more fields...
rstItems("ModelNumber").Value = ModelNumber
rstItems("HasUniqueID").Value = HasUniqueID
rstItems("IsPhysical").Value = IsPhysical
'Update the table
rstItems.Update
End Sub
I tried to simplify and clarify the code a bit, but you get the idea. Instead of having the query look up the manufacturer, I just did it in code so it could be added directly to the Items table.
Dan