Re: attribute type inheritence..

[sanjay jain <sanjay.jain@software.com>]

"Salter, Thomas A" wrote:

> Actually X.501 is pretty clear that only syntax and matching rules are
> inherited.
>
> 12.4.2 explicitly discusses inheriting syntax and matching rules.

> The ASN.1 definition of ATTRIBUTE defines default values for single-valued,
> collective, no-user-modification, and usage, so there is no possibility of
> inheriting them.

That's what I thought too ...

> Derivation, Type and the matching rules are all optional,
> with the note about one of Type or derivation being required.
>
> The only inheritance restriction (that I could find) is that user attributes
> and operational attributes can not inherit from each other.
>
> >From X.501,
> 12.4.6  Attribute definition
> Attributes may be defined as values of the ATTRIBUTE information object
> class:
> ATTRIBUTE       ::=     CLASS {
>         &derivation     ATTRIBUTE OPTIONAL,
>         &Type   OPTIONAL,       -- either &Type or &derivation required --
>         &equality-match MATCHING-RULE OPTIONAL,
>         &ordering-match MATCHING-RULE OPTIONAL,
>         &substrings-match       MATCHING-RULE OPTIONAL,
>         &single-valued  BOOLEAN DEFAULT FALSE,
>         &collective     BOOLEAN DEFAULT FALSE,
>         -- operational extensions --
>         &no-user-modification   BOOLEAN DEFAULT FALSE,
>         &usage  AttributeUsage DEFAULT userApplications,
>         &id     OBJECT IDENTIFIER UNIQUE }
> WITH SYNTAX {
>         [ SUBTYPE OF    &derivation ]
>         [ WITH SYNTAX   &Type ]
>         [ EQUALITY MATCHING RULE        &equality-match ]
>         [ ORDERING MATCHING RULE        &ordering-match ]
>         [ SUBSTRINGS MATCHING RULE      &substrings-match ]
>         [ SINGLE VALUE  &single-valued ]
>         [ COLLECTIVE    &collective ]
>         [ NO USER MODIFICATION  &no-user-modification ]
>         [ USAGE &usage ]
>         ID      &id }
>
>  > -----Original Message-----
>  > From: Kurt D. Zeilenga [mailto:Kurt@OpenLDAP.org]
>  > Sent: Thursday, July 13, 2000 2:14 PM
>  > To: sanjay jain
>  > Cc: ldapext
>  > Subject: Re: attribute type inheritence..
>  >
>  >
>  > At 10:48 AM 7/13/00 -0700, sanjay jain wrote:
>  > >Could somebody please clarify if any or all of
>  > >SINGLE-VALUE/MULT-VALUE, COLLECTIVE/
>  > >non-COLLECTIVE and NO-USER-MODIFICATION/
>  > >USER-MODIFICATION specs are inherited while defining
>  > >a new attribute type as a subtype of another attribute.
>  > >Its not clear to me either from RFC 2252 or X.501 (1993)
>  > >Section 12.4.2.
>  >
>  > X.501 could be clarified a bit in this area.
>  >
>  > I would think they should be inherited if not explicitly
>  > specified.
>  >
>  > foo;lang-en should be X if foo is X
>  >
>  > (where X is any of the above characteristics)
>  >
>  > I would also think some restrictions upon changes are likely
>  > appropriate.  I don't think it makes much sense to have a
>  > non-collective subtype of a collective attribute.
>  >
>  >