Subform will not work off a left join - need help

[dca]

I am working on a database to keep track of the devices in my SAN. Currently I have the following schema

Table KeyFields
SwitchInfo
ID (SwitchID)
ModelID
ModelInfo
ID (ModelID)
ModelMap
ID (MapID)
ModelID
Connections
SwitchID
MapID

I have a SwitchInfo form which has a connections subform. I would like to list all possible ports from the ModelMap table in this subform and then fill in the connection information. I tried using a query that joins the ModelMap and Connections but it would not allow a left join. I then tried to use the wizard and added the table fields directly to the subform. This only listed one line and when I added a record it added a record to the ModelMap table which I want to remain a static list of ports for each model of switch. When I add a connection for a port specified in the map I want to update the Connections table with the mapid key and the other fields in the connection table without changing the ModelMap table.

 

[Lilliabeth]

Main form: Switches
Subform: Connections

Delete the controls from the subform.
Replace them with a combo box that gets its values from ModelMap. Store the ID(MapID) value in MapID.

 

[dca]

I could use a combo box that lists the port number in column 2 and then uses column 1 to fill in the map-id in the connections table but this doesn't address some other issues. Each switch has a different port layout. Instead merely entering in connection information I was hoping the form would list all possible ports. This will help us visualize which ports are used versus those that are free.
I'm thinking I might have to generate a dynaset so that I can see this view and then after fields are updated in the dynaset I will have to use vba-ado to update the information in the actual tables.