Re: Relational database as backend?

[Mark Wilcox <mewilcox@unt.edu>]

Hi,
Luke's earlier message and Jeff's slides all point to this:
Objects don't map very well to Relational databases. This mapping can be done, but
it's not usually done very well, even by people who do this for a living.

Your point about putting data into a RDBMS so that can be made available from
other tools is a common one. However, the number of avialable APIs for LDAP is
growing and I think the majority of applications will be able to access LDAP
shortly either through commercial off-the-shelf plugins or through roll-your-own
gateways.

There will always be cases where you must keep data in both a RDBMS and  a LDAP
database, but with good design this can be minimal. Generally speaking white pages
information and information that is static in nature are good candidates for LDAP.
If you need to make complex queries on the data in particular where you need to
join a lot of data together in your queries, then use a RDBMs. (This is the major
point I think you get from the slides at Jeff's sight below)

Remember, pick the right tool for the job, not just the tool you know.

Mark



Daryl Biberdorf wrote:

> I'm a "mere" student administrator in a seminary program that
> keeps me pretty darned busy, so I'm reluctant to undertake
> a programming task at this moment.
>
> However, my interest in a relational backend is to allow
> other tools to access the information. In particular,
> I felt being able to use commonly available tools like
> Access or PowerBuilder (my own field of expertise) would
> be useful to us.
>
> The first presentation mentioned (your own) mentions performance
> problems with using a relational backend. Other than the standard
> "low-overhead network/hierarchical database versus high-overhead
> relational database" issue, I can't see how the relational database
> would be a problem. (I'm new to LDAP, so please forgive my complete
> ignorance of its schema.)
>
> My own area of professional expertise (prior to coming to the
> seminary one year ago) is information systems, particularly
> client/server relational databases and associated tools.
> Databases are used quite a bit for just the sort of stuff that
> LDAP is storing, and performance is quite good. With the increase
> in replicaton offerings from the major vendors (Sybase comes
> to mind), would that replication make LDAP's replication
> superfluous?
>
> At this point, I'd like to hear more about the specific
> aspects of LDAP that would prevent good performance in a
> relational database. Please don't take any of this as
> argumentative. I'm just an LDAP newbie trying to learn.
>
> Daryl
>
> On Sun, 25 Oct 1998 Jeff.Hodges@stanford.edu wrote:
>
> > mewilcox@unt.edu said:
> > > Netscape Directory server allows you to use a RDBMS backend if you
> > > don't mind writing some code (you have to write your own server plugin
> > > to lookup stuff in a RDBMS). I don't think openLDAP supports this yet.
> > > Other packages might as well, though I don't know about them.
> >
> > UMich LDAP release 3.3, and thus OpenLdap 1.0, ~does~ support pluggable
> > backend databases. Layering slapd on top of an RDBMS is a SMOP (small matter
> > of programming). Tho, one has to carefully consider ~why~ one'd want to do
> > that. As pointed out in prior messages, these slides & doc discuss such
> > matters...
> >
> >   http://www.stanford.edu/~hodges/talks/EMA98-DirectoryServicesRollout
> >     /Steve_Kille/index.htm
> >
> >   http://www.isode.com/IC-6055.html

--
Mark Wilcox
mewilcox@unt.edu
University of North Texas  (940)565-2568
http://www.unt.edu/
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