Re: order of attribute values

[Howard Chu <hyc@symas.com>]

Forest Hill wrote:
> In current implementations OpenLDAP (2.2.x & 2.3.x) what's the stand 
> of guaranteeing order of attribute values? I've always been under the 
> assumption that there was no guarantee of preservation of attribute 
> value order. Can someone clarify this?
The X.500 and LDAP specifications explicitly state that order is not 
preserved and must not be relied on. In OpenLDAP 2.3 we've implemented a 
number of extensions that allow the order of values in multi-valued 
attributes to be preserved. The first is the X-ORDERED 'VALUES' 
extension which may be specified in an attribute's schema definition. I 
have discussed this extension at length in earlier posts to this list, 
check the archives for more details.

Also in 2.3 is the valsort overlay which allows multi-valued attribute 
values to be ordered dynamically based on simple sorting rules (alpha / 
numeric ascending / descending, weighted). See the slapo-valsort(5) 
manpage for more details.

RFCs for both of these features will be coming out in the near future. I 
don't know that they need to progress to anything more than 
Informational status, but we'll see.

--
 -- Howard Chu
 Chief Architect, Symas Corp.  http://www.symas.com
 Director, Highland Sun        http://highlandsun.com/hyc
 OpenLDAP Core Team            http://www.openldap.org/project/