Old thread, but wanted to reply, since I just ran into this on 11.5(1)SU5
If you read the data dictionary, it states that if "Use System Defaults" is set across the board for a relationship, that the record in the regionmatrix table should be deleted.
Therefore, the command would be:
run sql delete from regionmatrix where <your limiting clause here>
Now, you want to make sure you're only modifying the relationships which you intend to, and a slip up on the where clause could result in your defaulting every single relationship in the system.
If you want to default just a single relationship, then you might do this:
! Get the PKID in the regionmatrix table where your two regions have a relationship
run sql select pkid from regionmatrix where (fkregion_a = (select pkid from region where name = 'test1') and fkregion_b = (select pkid from region where name = 'test2')) or (fkregion_a = (select pkid from region where name = 'test2') and fkregion_b = (select pkid from region where name = 'test1'))
! Then use the output of that command to remove the relationship from the table
run sql delete from regionmatrix where pkid = '<the value from the previous command>'
If you were instead defaulting multiple relationships to a single region, then actually, I would suggest using the same method as above, but once for each relationship.
Now, if you wanted to default all relationships that a single region has, then you might do this:
! Get your region's PKID
run sql select pkid from region where name = 'test1'
! Remove the records from regionmatrix where this region is involved (can be either region_a or region_b)
run sql delete from regionmatrix where fkregion_a = '<the value from the previous command>' or fkregion_b = '<the value from the previous command>'
And lastly, if you're trying to depopulate the entire region matrix, so that every region relationship defaults to using the system defaults, then you'd do this:
run sql delete from region matrix
You could get a little fancier and perhaps do some of these in a single command, but I like the separation of the two.
