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From David Boreham <david_l...@boreham.org>
Subject Re: ApacheDS partition implementation based on Relational Model
Date Thu, 02 Nov 2006 15:29:36 GMT
Ersin Er wrote:

> I need some advice on implementing a partition for ADS based on the
> relational model and using SQL or Hibernate or JPA, or framework like
> them..

First the $64,000 question : WHY ?

> First of all, is this realistic? Can we reach a usable result?

Yes, but experience shows that it's typlically not worth the trouble.
There are two common reasons for wanting such a thing:

1. 'Datastore envy' : 'I want all my data in Oracle' (because Larry says 
so).

2. Adapting existing data (hey, all our HR stuff is in an Oracle database
underneath Peoplesoft, let's expose that using LDAP).

The trouble with #1 is that once whoever it is that's asking
is told the cost and hassle involved vs just using a perfectly
working LDAP server that already exists, they tend to forget
their datastore envy.

The trouble with #2 is that it turns into an object relational mapping
science project. Very hard to say in advance what kinds of mapping
are needed without seeing the use cases. So it tends to deflate into
'well we can write some custom hack for each individual customer'
and 'hmm...syncing the data using a metadirectory solution is much
easier'.

> Can we leverage the power of SQL SELECT for LDAP search operations?

The simplest way to do it is to construct tables that look just like the
b-tree relations used in a custom LDAP data store. However this doesn't
goal achieve #2 above.

There have been some successful LDAP server products that
_only_ used the relational database store technique : IBM had one
and so did(does?) Oracle.



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