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From Alex Karasulu <aok...@bellsouth.net>
Subject Re: ApacheDS partition implementation based on Relational Model
Date Thu, 02 Nov 2006 18:35:21 GMT
Ersin Er wrote:
> Hi,
> 
> On 11/2/06, David Boreham <david_list@boreham.org> wrote:
>> 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 ?
> 
> Well, this is just a test currently. It's a software engineering
> project for two students to make them familiar with all these (ldap,
> rdbms, ADS, pragmatic tools, etc.) stuff. It can also be thought as a
> DB research project to learn what the best way of storing directory
> data on RDBMS is.
> 
>> > 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.
> 
> Can you explain this more?

Basically he's saying model the db like you do the jdbm tables in the 
ldbm rip off we use for the default backing store.

Meaning you have a master table, an id2dn table, and so on just like 
using jdbm tables.

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


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