Hi Eliseo,

There’s two sides to this:

- getting the new subjects created

- moving eprints from the old subjects to the new ones.

If possible, I’d look at getting the new subjects into order first – as you’ve already identified, either via the web interface or the import (you might want to look at the subject export too – which might be useful to do, add your new subjects and then re-import).

Creating a new set of nodes is (IMO) easier than trying to rework the existing ones as they are stored in the database as both child and parent trees, so you’d possibly have to make changes to stuff in all these tables:

subject

subject__index

subject__index_grep

subject__ordervalues_en

subject__rindex

subject_ancestors

subject_name_lang

subject_name_name

subject_parents

To move the eprints from one node to another, if it’s a straight swap (e.g. subjectid_A is replaced by subjected_1; subjectid_B is replaced by subjectid_2 etc.), it’s fairly easy to do in the database (you could even clone the eprint_subjects table and do the updates in the new copy to be on the safe side).

mysql> UPDATE eprint_subjects SET subject = newSubjectID where subject = oldSubjectID;

I find the following query useful to see if there are any subjects use, but not defined:

mysql> select count(*),  subject, pos from eprint_subjects where subject NOT IN (select subjectid from subject) group by subject, pos;

Hope that helps a bit – someone else might have some better/easier ways of doing this!

Cheers,

John

Hi,

I know that we can add and edit the subjects by logging in as admin and can also import a subject_xml file, but  If we are to merge some subjects with different subject code into one, is there an automatic way to update the subject codes for the items already submitted in the archive?

I saw the eprints_subject table wherein we can replace the subject field with the new codes and update the items but I’m not sure if there are anything else that we need to update?

Thanks!