I’d like to know when using the DB and not side car files for raw editing, do we lost all editing on images when migrating from PL2 to PL3 ? Or is there a migrating tool to convert editing from one verison to another ?
And if all answers are “No” , is it different with side car files ?
Yes, DB is migrating and you do not lose any of your corrections (DB contains all the corrections you made to the images).
Sidecars are useful for the other case: for example when you want to have same corrections on the images when you open them on the other machine.
As it has already been pointed here above - you can create a DB backup and restore it for example PL1 backup can be restored in PL3.
So in short words: DB is most useful when you work on the same machine, sidecars when you transfer your images to the other machine (it’s in case of migration of the corrections). Guys on the Forum can suggest other cases when sidecars are useful.