When we use compare and merge to update the PDM from the LDM (within a single dm1 file), the attributes and columns don't always match up. I know we can force-match them, but we've found that they match up if we make sure that the 'physical name' on an attribute is the same as the actual name of the column.
This raises several points
BTW, we're still using XE4
I don't remember if this is available in XE4, but once you force match these objects together there is an option to save the matches. On page 5 of the compare wizard you should see a checkbox that looks like this:
If you check it and then click on the ... button you'll have the option to save the mappings.
Once you do that the next time you want to run a compare and merge, those matches you've forced should always match up.
You can also modify the where used to match up the objects but this usually only works on models in the same dm1 file.
Hopefully this answers some of your questions. There isn't an easy way to match up columns in different models if they don't have a "history" with each other (ie, merged or generated from a model). You have to do the force matching manually but this option allows you to save those force matches so that at a later date you won't need to force match again.
In reply to Stanley Chan:
In reply to George McGeachie:
In reply to Jason H: