What does
Update tags (From Library) and
UPdate Library (from Tags)
Exactly do?
My observations are that:
UPdate Library (from Tags) : MJ takes the tag values and writes them into the library, eventually replacing existing values. I don't know what about db fields that do not exist in the tags; are they set to 'empty' ? are they unchanged ?
Update tags (From Library) :
- existing tags that exist also in db: MJ updates their values from the related db value
- existing tags that do not exist in db: MJ let them inchanged
- db fields that do not exist in tags: MJ creates the tags if the tag type allow it
There is a specific behaviour the first time MJ9 updates MJ8 tags: MJMD tag is replaced by several COMM tags.
Otherwise if you want to remove existing tags that don't have a corresponding db field (such as TENC or USER) you need to 'remove tag' and then 'Update tags (From Library)'
but be careful if you have embedded cover art: you will loss them !