[Deprecated] DMZ 1.5.3 (DataMapper OverZealous Edition)

[eluser]OverZealous[/eluser]
Except, you don't need joining tables.

The MachineParts table can contain machine_id and part_id.

What you are effectively doing is converting the machines_parts joining table (which is merely used to represent a relationship) into a full model (MachineParts). This model can then be used to link the same part to the same machine multiple times.

Code:

Table:Machine --&gt; Table:MachineParts <-- Table:Parts
ID 1              ID 1, MID 1, PID 8     ID 8
ID 1              ID 2, MID 1, PID 8     ID 8
ID 1              ID 3, MID 1, PID 9     ID 9
ID 1              ID 4, MID 1, PID 9     ID 9
ID 2              ID 5, MID 2, PID 8     ID 8
ID 2              ID 6, MID 2, PID 9     ID 9
     ...                 ...                ...

Then read over the code from a few posts ago (excluding the lookup, look to the last one I posted).

The biggest drawback to this method is that you lose the ability to look up or save parts like this:

Code:

// NO LONGER WORKS!
$machine->parts->get();
$machine->save($part);
// NO LONGER WORKS!

The benefit is you can now have multiple joins between the same machine and part, and you can more easily store additional information about the join (including validation rules).