Grouper Developers Forum

["GW Brown, Information Systems and Computing" <>]

--On 10 June 2008 09:17 -0500 Tom Zeller 
<>
 wrote:

> This is already a rather long thread, and I'm loathe to add more to it,
> but...
>
> Representing changes from a group-centric point of view via LDIF seems
> straightforward, but what about member-centrically ? e.g. how someone's
> group memberships have changed.
What is the context here? Are we back to the subject id changing or is this 
to make it easier to query from a member point of view i.e. show me all the 
memberships for 'x' on a given date?
> Group-centrically :
>
>
> dn: name=stem:group,uuid=...
> add: members
> members: subject...
>
>
> Member-centrically ?
>
>
> dn: name=subject
> add: groups
> groups: stem:group
>
>
> Doesn't seem right to me. I imagine we would want to be able to easily
> query for changes affecting a member, and consequently it seems we would
> probably want to add the member (or it's subject id) as a column, and
> hence we would want one row per membership change...which makes me think
> LDIF isn't the right way.
One row per membership change wouldn't be down to the LDIF format - it 
would mean we are not storing enough metadata in the database table. I 
hadn't thought about looking from the member perspective. In principle we 
should be able to do this, but one row per membership change doesn't strike 
me as scalable. If the actual change definitions  - the LDIF or whatever 
format we use - for a group can be queried using 'like' we could have an 
inefficient means of finding relevant changes which would allow us to 
compute a subject's memberships at a given point in time.

In the end it could come down to how often we need to ask questions of the 
change log. If infrequently we can live with slower response times.

Another approach would be to have an asynchronous process for expanding the 
'batch' group membership changes into one row per change so that it does 
not slow down the API.
> TomZ



----------------------
GW Brown, Information Systems and Computing