Understanding Matching Rules124 Netscape Directory Server Plug-In Programmer’s Guide • May 2002Extensible Match FiltersIn an “extensible match” filter, the client specifies that it wants to use the matchingrule to compare a specified value against the values of entries in the directory. (Forexample, an extensible match filter might find all entries in which the sn attribute“sounds like” melon.)An “extensible match” filter contains the following information:• The OID of the matching rule or the attribute type that you want to search (orboth)• The value to search for• A preference indicating whether or not to also search the attributes in the DNFor example, if the OID “1.2.3.4” identifies a matching rule that performs “soundslike” matches, the following extensible match filter attempts to find entries wherethe mail attribute “sounds like” moxie.(mail:1.2.3.4:=moxie)In the search filter, the client can specify the OID (that identifies a matching rule)and the attribute type. This indicates that the value in the filter should be comparedagainst the attribute using the matching rule.For example, if the OID 1.2.3.4 specifies a “sound-alike” match and if the stringrepresentation of the search filter is:(uid:1.2.3.4:=moxie)the client wants to find entries in which the value of the uid attribute sounds likemoxie.Note that although the LDAP v3 standard allows clients to omit the OID or theattribute type, at this time, the Netscape Directory Server only supports extensiblematch filters that specify both the OID and attribute type.The filter can also specify a preference indicating whether or not to also search theattributes in the DN. For example, if the OID 1.2.3.4 specifies a “sound-alike”match and if the string representation of the search filter is:(sn:dn:1.2.3.4:=moxie)the client wants to find all entries in which the value of the sn attribute or theattributes in the DN (for example, uid, cn, ou, or o) sound like moxie.
