Merging and transferring databases and content from V2 to a new V3 setup

Hi Steve, 

I like Jeff's idea of creating a num_old field to store the original num value.  What I'd recommend is doing a test merge with just two tables to start.  We don't have the exact process documented, it's just something we figure out when we need to do it, but I'm happy to give you some tips.

a) where do I upload the newly amended uploads tables? Do I import then into the same business_advertising table and if so how/where do I map the fields or do I create a new uploads table.

There's one universal uploads table that is independent of all the tables.  You just need to import that table and change the record num and table name fields from the old values to the new values and the uploads should appear.

b) providing the user accounts table was imported with num mapped to num will the records in the business_advertising table be automatically associated with the correct user account? ie the createdBy field value in each table will still match the num field in the user accounts.

Yes, as long as the user num value isn't changed and the createdByUserNum value isn't changed.

c) When I upload the image folder contents, If I dont upload the Thumbs folders will that allow me to re-create the thumbs to the sizes required for the new site design without causing any issues.

Yea, I think so.  And even if you uploaded all the thumbs they should just get overwritten if you changed the size and click recreate in the field editor to regenerate them.

d) would I be better when importing the new uploads table to not map the "thumbs" fields if we intend to recreate those to a new format?

I would just leave them as-is, they should get recreated when you click the recreate button in the field editor.

e) once we have the new site design finished with all the databases fully populated we will need to transfer everything to the normal host site, will any of what I do above cause any potential issues when moving everything across to a different domain name?

It shouldn't, no.  Just make sure you don't have any images, urls, etc hard coded in wysiwyg or other content with fully qualified URLS (eg: http://www.example.com/file.jpg").  By default they shouldn't be.  And you can also try a test restore on a different domain to be extra safe.  And be sure to backup the original site before you replace it.  

Hopefully clarification to the above will mean that I can not just start but successfully complete the import process.

Good luck!  Take your time and make backups so you can restore at any point if you run into an issue.