Re: Objectclass-Definitions

[Giovanni Baruzzi <giovanni.baruzzi@allianz-leben.de>]

Stefan Kiesow wrote:

> Hello,
>
> I have the following questions:
>
> First:
> ------
> I need to built a new Objectclass to organize information about people of an
> organization.
> Therefore I would like to extend existing classes for my needs. Is it
> possible to do so? If yes, how do I have to derive a new class from an
> existing one and how can I extend it?
>

This is the correct approach. How to do it depends from your Directory Server,
unter Netscape you can do it interactivley; for other servers try to look for
the files slapd.oc.conf and slapd.at.conf.

Try to hang at the standards as long as possible; try to understand the meaning
and the purpose of every attribute, and employ this attribute as was originally
planned.
Set as less constraints as possible, don't use masks for telephone numbers,
don't use many fields for things that can be different in various places on the
Earth (addresses!!!) but think to use the fact that an attribute can have many
values (telephone number) or that an attribute can have many lines (I have used
the field "address" to store international addresses using <br> as line break
and the decision proved to be a very good one).

One more word of caution: when modeling, absolutely describe properties of the
object you are modeling and not properties of you application. This happens much
often than desirable and prevents the reuse of you data in DIT.


>
> Second:
> ---------
> I've recognized, that for the Objectclass umichPerson many attributes are
> used, which I can't find in the slapd.at.conf files.
> Isn't it necessary to define all attributes I'd like to use for my purposes?
>

umichPerson is not standard.
Please use the standards as long as possible.
Much of the standards are derived form X.500; you may give a look there.
Interesting information is found at the sites of Netscape
(developer.netscape.com) and OpenLDAP (www.openldap.com)


>
> Third:
> ------
> When I use such a self-constructed class, what about the attributes? When I
> use Netscape or Internet-Explorer's addressbook, the attributes cn, mail,
> etc. are used. Depends the use of these attributes also on the objectclass
> in which these attributes are declared?

The attributes and their use is extremely important. Perhaps much more important
of the class itself.
Hence is important to use standard attributes and to use them properly, along
the scope for which they had been originally designed. Much of the difficulties
that we have today to let interoperate Netscape and MS are due to different
interpretation of the standard attributes.




> Or do Netscape and other
> applications only look for these attributnames regardless the class they
> belong to?
>

Exaclty so: the class is not important: what is being sought is the attribute.


>
> Thanks for help,
> Stefan Kiesow