[OPEN-ILS-DEV] Merging Patrons

[Mike Rylander]

On Tue, Aug 19, 2008 at 1:13 PM, Jason Etheridge <jason at esilibrary.com> wrote:
>>>> Sounds like a good possibility.  I just wonder how (or if) you could tease apart transactions that happened after the merger, particularly if there is more than one active card attached to the record, and the transactions happened after retrieving the user by name or other access point so you don't know for sure which card to attach the new transactions to.
>>>
>>> [splitting users by splitting cards, and which card to put new transactions on]
>>> However, if the patron was retrieved by a different
>>> means, it'd be a bit klunky/inelegant to ask staff which card is being
>>> used for that session.
>>
>> Sounds like another use for actor.usr.card. ;)
>
> Well, the whole point of unmerging patrons is to fix a mistake, and if
> you've mistakenly merged two patrons, then what are the odds of
> post-merge-pre-unmerge transactions going onto the right card whenever
> the actual physical card is not present?  Selecting one with
> actor.usr.card doesn't seem to improve the odds by itself.

My point was that it's better than an arbitrary/random card.  There
are cases where information is not available, and having a predictable
outcome is always better than a random one.  The way to get all the
way past this is to /require/ a card for circulation -- which would be
a step back.

The other part to consider is 1) how often will a merge occur (I mean,
is it something that would happen often enough that mistakes would be
probable) and 2) from that (assumed small) set of merges, how often
would a split be required after some amount of time had passed?

My guess would be (for things other than migration, and that's another
story altogether) the answer to 1) is "very seldom" and the answer to
2) would be on the order of "once per epoch" ... but, that's just a
guess and I'd love to get real numbers.

-- 
Mike Rylander
 | VP, Research and Design
 | Equinox Software, Inc. / The Evergreen Experts
 | phone: 1-877-OPEN-ILS (673-6457)
 | email: miker at esilibrary.com
 | web: http://www.esilibrary.com