Re: logic of approx search in ldap

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

At 06:02 AM 6/7/2006, Nasrin.N@xansa.com wrote:
>Please explain what happens when searched by filter approx ("~=").  It will 
>be very helpful if you specify some examples along with algorithm used in 
>the background.

For attributes with caseIgnoreMatch or caseExactMatch equality
rule, a basic description (with examples) of the basic algorithm
used in slapd(8) can be found in Section 4.2 of "An X.500 and LDAP
Database: Design and Implementation" by Tim Howes (U. of Michigan)
(available at:   http://www.openldap.org/pub/umich/xldbm.pdf>).

slapd(8) implements approximate rules for attributes of various
other equality rules, and where it doesn't, falls back to the
equality rule.

See the code for particulars.

I note that the approximate code has changed a bit over the
years and it likely will continue to change, so your mileage
may vary.  Of course, with approximate matching, one should
never rely on any particular matching behavior (other than
X match Y if X and Y are equal per the equality rule)

Kurt


>Thanks & Regards,
>Nasrin.N
>Software Engineer,
>Lawson 
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