Schema support

[Michael Ströder]

Hans Aschauer wrote:
> 
> Ok, I went back to RFC 2251. That's how I understand it (please correct 
> me when I'm wrong):
> 
> Sec. 3.4: 
> We can query the RootDSE for the subschemaSubentry attribute, which 
> tells us which "subschema entries (or subentries) [are] known by this 
> server":
> 
> [aschauer at pygar]$ldapsearch -LLL -x -b "" -s base "(objectclass=*)" \
> 	subschemaSubentry
> dn:
> subschemaSubentry: cn=Subschema

Hmm, BTW it does not clarify how a client should deal with a multi-valued 
subschemaSubentry attribute. Should schemas be used exclusive-or or joined. 
That's another interesting topic to be discussed in IETF ldap-bis WG.

> So, as far as I understand it, we should first query the rootDSE for 
> the subschema (sub)entries, and use the results as search bases for 
> querying the schema information. 

Take also a look at section 3.2.1.:

--------------- snip -----------------
3.2.1. Attributes of Entries

[..]
    Entries MAY contain, among others, the following operational
    attributes, defined in [5]. These attributes are maintained
    automatically by the server and are not modifiable by clients:
[..]
    - subschemaSubentry:  the Distinguished Name of the subschema entry
      (or subentry) which controls the schema for this entry.

--------------- snip -----------------

So my conclusion is that an application should first try to query 
operational attribute subschemaSubentry for a particular entry and fall-back 
to the subschemaSubentry attribute in the root DSE to find out the location 
of sub schema sub entry in the DIT. Puh...

I guess I will start a discussion about that on the ldap-bis list.

Ciao, Michael.