I had the same problem. The only way I could get a product to associate to a Manufacturer (giving the ability to group by manufacturers when browsing the store) was to load each product individually and “Save” the product. Didn’t require any changes to the actual product as it had the correct Manufacturer in the drop down, just needed to be saved again.
I also tried doing updates in groups, but unfortunately that didn’t work. You had to do it individually on each product. Because I needed to get this site out the door, I had to do this for about 450 products. Not fun.
So anyway I did a bit of digging.
After doing what I mentioned above, I found that it does some fairly major alterations to the database. It’s almost as if it sees that the data is of the old format, then munges it around to suit the current table layouts and data structures.
I’ve attached the diff, it’s 411 lines long. I dumped the db, “saved” 1 product, then redumped the db and diffed the mysql xml output. Needless to say there’s a lot going on when you save a product.
Magento devs, it would be really handy if there was a database cleanup script or something along those lines where it would go through sequentially on each product and clean up the data structures to suit the current version.
Please tell me this doesn’t already exist.... *eek*
FYI, I deleted all products first with help from this post - http://www.magentocommerce.com/boards/viewthread/5120/P45/ - then re-imported an excel exported CSV into the db. Still no love associating products to manufacturers. Is the import script dropping data in using old data structures?
It would be really handy if manufacturers were created dynamically on a product import, so you could start with a fresh copy of Magento and just stuff everything into it in one go… I’m currently using 1.1.3, upgraded from 1.0