how to deal with unique keys in some tables? about moodle-tool_mergeusers HOT 2 CLOSED

This issue has been resolved by correct configuration of the plugin in the last version of this plugin.

The idea behind that is all cases the same:

Context

We have an olduserid and a newuserid. The olduserid is related to a user to be replaced by the user related to newuserid. In other words, all records related to olduserid will be presented as if they were performed by newuserid.

In some database tables, there are indexes that are compound by several fields (now on compound indexes) relating at lest a user-friendly field. Actually, we have only found compound indexes made by two fields. And in some cases, both fields are user-friendly.

How does the plugin process compound indexes?

Let us suppose the following scenario in a given database table with an identified case of compound index:

1. If the table has a record where only the olduserid value appears, the plugin simply replaces the olduserid value by the newuserid without conflict, like in the rest of normal cases.
2. If the table only has cases on which a record appears with only the newuserid value on, the plugin simply ignores that case. The database table already presents the value we expect.
3. If the table has for a given compound index value both the olduserid and newuserid values, the plugin realizes the following:
   1. Deletes the records related to olduserid for conflicting cases on compound indexes if they were replaced with the newuserid value.
   2. We leave with no change the records related to newuserid. We assume that, given the olduserid has to disappear and that it is older than the newuserid, the related records of newuserids are equivalent to the records from olduserid. In other words, the person related to the given olduserid and newuserid has made the same "job" for both olduserid and newuserid.

Let you check how it works just now 👍

from moodle-tool_mergeusers.

Hi Jordi,
Indeed, I think your assumption (3.ii.) is correct, and that solved the problem. Brillant!

from moodle-tool_mergeusers.