Attribute Type Description Format

The attribute type description format is described in RFC 4512, section 4.1.2 as shown here:

AttributeTypeDescription = LPAREN WSP
    numericoid                    ; object identifier
    [ SP "NAME" SP qdescrs ]      ; short names (descriptors)
    [ SP "DESC" SP qdstring ]     ; description
    [ SP "OBSOLETE" ]             ; not active
    [ SP "SUP" SP oid ]           ; supertype
    [ SP "EQUALITY" SP oid ]      ; equality matching rule
    [ SP "ORDERING" SP oid ]      ; ordering matching rule
    [ SP "SUBSTR" SP oid ]        ; substrings matching rule
    [ SP "SYNTAX" SP noidlen ]    ; value syntax
    [ SP "SINGLE-VALUE" ]         ; single-value
    [ SP "COLLECTIVE" ]           ; collective
    [ SP "NO-USER-MODIFICATION" ] ; not user modifiable
    [ SP "USAGE" SP usage ]       ; usage
    extensions WSP RPAREN         ; extensions

usage = "userApplications"     /  ; user
        "directoryOperation"   /  ; directory operational
        "distributedOperation" /  ; DSA-shared operational
        "dSAOperation"            ; DSA-specific operational

The attribute type description includes these elements:

numericoid

The numeric OID used to uniquely identify the attribute type in the directory server. Although the specification requires a numeric OID, the directory server also allows a non-numeric OID for the purpose of convenience and better compatibility with the Sun Java System directory server. In this case, the non-numeric OID should be the same as the name of the attribute type followed by the string -oid.

NAME

An optional set of human-readable names that can also be used to refer to the attribute type. If there is a single name, then it should be enclosed in single quotes. If there are multiple names, then they should each be enclosed in single quotes separated by spaces, and the entire set of names should be enclosed in parentheses.

DESC

An optional human-readable description. If there is a description, then it should be enclosed in single quotation marks.

OBSOLETE

An optional OBSOLETE flag that can be used to indicate whether the attribute type is active. If an attribute type is marked as OBSOLETE, then it means that it should not be referenced by any new elements created in the directory server.

SUP

An optional reference to the superior attribute type. If there is a superior type, then it may be referenced by either its OID or any of its human-readable names.

EQUALITY

An optional equality matching rule definition. If a specific equality matching rule is provided, then it can be referenced by either its OID or any of its human-readable names. If no equality matching rule is given, then the attribute type uses the default equality matching rule for the associated attribute syntax. If the attribute syntax does not have a default equality matching rule, then equality matching operations are not allowed for attributes of that type.

ORDERING

An optional ordering matching rule definition. If a specific ordering matching rule is provided, then it can be referenced by either its OID or any of its human-readable names. If no ordering matching rule is given, then the attribute type uses the default ordering matching rule for the associated attribute syntax. If the attribute syntax does not have a default ordering matching rule, then ordering matching operations are not allowed for attributes of that type.

SUBSTR

An optional substring matching rule definition. If a specific substring matching rule is provided, then it can be referenced by either its OID or any of its human-readable names. If no substring matching rule is given, then the attribute type uses the default substring matching rule for the associated attribute syntax. If the attribute syntax does not have a default substring matching rule, then substring matching operations are not allowed for attributes of that type.

SYNTAX

An optional attribute syntax for use with the attribute type. If it is provided, then it should be given as a numeric OID. The syntax identifier can also optionally contain an integer value enclosed in curly braces directly following the OID (without any spaces between the last digit of the OID and the opening curly brace), which may be used to suggest a minimum upper bound on the length of values for attributes of that type. The directory server does not enforce any maximum length restrictions for attribute values, so if a length is given, then it is ignored.

SINGLE-VALUE

An optional SINGLE-VALUE flag that indicates that attributes of that type are allowed to have only a single value in any entry in which they appear. If this flag is not present in the attribute type description, then attributes of that type are allowed to have multiple distinct values in the same entry.

COLLECTIVE

An optional COLLECTIVE flag that indicates that the attributes of that type are assigned their values by virtue in their membership in some collection. Collective attributes are described in RFC 3671 (Collective Attributes in LDAP) and are one of the types of virtual attributes that are supported in the directory server.

NO-USER-MODIFICATION

An optional NO-USER-MODIFICATION flag that indicates that values of attributes of that type cannot be modified by external clients (that is, the values can be modified only by internal processing within the directory server).

USAGE

An optional usage specification that indicates how the attribute type is to be used. The following attribute usages are allowed:

userApplications

Used to store user data.

directoryOperation

Used to store data required for internal processing within the directory server.

distributedOperation

Used to store operational data that must be synchronized across servers in the topology.

dSAOperation

Used to store operational data that is specific to a particular directory server and should not be synchronized across the topology.

extensions

An optional set of extensions for the attribute type. The directory server currently uses the following extensions for attribute types:

X-ORIGIN

Provides information about where the attribute type is defined (for example, whether it is defined by a particular RFC or Internet Draft or whether it is defined within the project).

X-SCHEMA-FILE

Indicates which schema file contains the attribute type definition.

X-APPROX

Indicates which approximate matching rule should be used for the attribute type. If this is specified, then its value should be the name or OID of a registered approximate matching rule.

For example, the following is the attribute type description for the standard uid attribute type:

( 0.9.2342.19200300.100.1.1 NAME 'uid' EQUALITY caseIgnoreMatch
SUBSTR caseIgnoreSubstringsMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15{256}
X-ORIGIN 'RFC 4519' )

In this case, the OID is 0.9.2342.19200300.100.1.1. There is a single human-readable name of uid. The caseIgnoreMatch rule should be used for equality matching, and the caseIgnoreSubstringsMatch rule should be used for substring matching. The attribute type uses the directory string syntax with a suggested minimum upper bound of 256 characters, and the attribute type definition was taken from RFC 4519. There is no description or superior type specified. The attribute type is not marked OBSOLETE, SINGLE-VALUE, COLLECTIVE, or NO-USER-MODIFICATION. There is no ordering matching rule specified, which means that the directory server falls back on the default ordering rule used by the directory string syntax. There is no X-APPROX extension to specify the approximate matching rule so the default approximate rule for the directory string syntax is used there as well.