# $OpenLDAP$
-# Copyright 1999-2000, The OpenLDAP Foundation, All Rights Reserved.
+# Copyright 1999-2003, The OpenLDAP Foundation, All Rights Reserved.
# COPYING RESTRICTIONS APPLY, see COPYRIGHT.
H1: Schema Specification
-This chapter describes how to extend the schema used by {{slapd}}(8).
+This chapter describes how to extend the user schema used by {{slapd}}(8).
The first section, {{SECT:Distributed Schema Files}} details optional
schema definitions provided in the distribution and where to obtain
other definitions.
to {{slapd.conf}}(5) format.
!endif
+This chapter does not discuss how to extend system schema used by
+{{slapd}}(8) as this requires source code modification. System
+schema includes all operational attribute types or any object class
+which allows or requires an operational attribute (directly or
+indirectly).
+
+
H2: Distributed Schema Files
OpenLDAP is distributed with a set of schema specifications for
{{F:/usr/local/etc/openldap/schema}} directory.
!block table; colaligns="LR"; coltags="F,N"; align=Center; \
- title="Table 6.1: Provided Schema Specifications"
+ title="Table 8.1: Provided Schema Specifications"
File Description
core.schema OpenLDAP {{core}} (required)
cosine.schema Cosine and Internet X.500 (useful)
inetorgperson.schema InetOrgPerson (useful)
misc.schema Assorted (experimental)
-nadf.schema North American Directory Forum (FYI)
nis.schema Network Information Services (FYI)
openldap.schema OpenLDAP Project (experimental)
!endblock
To use any of these schema files, you only need to include the
-the desired file in the global definitions portion of your
+desired file in the global definitions portion of your
{{slapd.conf}}(5) file. For example:
> # include schema
Note: You should not modify any of the schema items defined
in provided files.
+
H2: Extending Schema
Schema used by {{slapd}}(8) may be extended to support additional
-syntaxes, matching rules, attribute types, and object classes.
-This chapter details how to add attribute types and object classes
-using the syntaxes and matching rules already supported by slapd.
-slapd can also be extended to support additional syntaxes
-and matching rules, but this requires some programming and hence
-is not discussed here.
+syntaxes, matching rules, attribute types, and object classes. This
+chapter details how to add user application attribute types and
+object classes using the syntaxes and matching rules already supported
+by slapd. slapd can also be extended to support additional syntaxes,
+matching rules and system schema, but this requires some programming
+and hence is not discussed here.
There are five steps to defining new schema:
^ obtain Object Identifer
+ define custom attribute types (if necessary)
+ define custom object classes
+
H3: Object Identifiers
Each schema element is identified by a globally unique
the tree as follows:
!block table; colaligns="LR"; coltags="EX,N"; align=Center; \
- title="Table 6.2: Example OID hierarchy"
+ title="Table 8.2: Example OID hierarchy"
OID Assignment
1.1 Organization's OID
1.1.1 SNMP Elements
!endblock
You are, of course, free to design a hierarchy suitable to your
-organizational needs under your organization's OID. No matter
-what hierarchy you choose, you should maintain a registry of
-assignments you make. This can be a simple flat file or a
-something more sophisticated such as the {{OpenLDAP OID Registry}}
+organizational needs under your organization's OID. No matter what
+hierarchy you choose, you should maintain a registry of assignments
+you make. This can be a simple flat file or something more
+sophisticated such as the {{OpenLDAP OID Registry}}
({{URL:http://www.openldap.org/faq/index.cgi?file=197}}).
-For more information about Object Identifers (and a listing
-service) see {{URL:http://www.alvestrand.no/harald/objectid/}}.
+For more information about Object Identifers (and a listing service)
+see {{URL:http://www.alvestrand.no/harald/objectid/}}.
-.{{Under no circumstances should you use a fictious OID!}}
+.{{Under no circumstances should you hijack OID namespace!}}
-To obtain a fully registered OID at {{no cost}}, apply for
-an OID under {{ORG[expand]IANA}} (IANA) maintained
-{{Private Enterprise}} arch. Any private enterprise (organization)
-may request an OID to be assigned under this arch. Just fill
-out the {{ORG:IANA}} form at {{URL: http://www.iana.org/cgi-bin/enterprise.pl}}
-and your official OID will be sent to you usually within a few days.
-Your base OID will be something like {{EX:1.3.6.1.4.1.X}} were {{EX:X}}
+To obtain a registered OID at {{no cost}}, apply for an OID under
+the {{ORG[expand]IANA}} (IANA) maintained {{Private Enterprise}}
+arc. Any private enterprise (organization) may request an OID to
+be assigned under this arc. Just fill out the {{ORG:IANA}} form
+at {{URL: http://www.iana.org/cgi-bin/enterprise.pl}} and your
+official OID will be sent to you usually within a few days. Your
+base OID will be something like {{EX:1.3.6.1.4.1.X}} where {{EX:X}}
is an integer.
-Note: Don't let the "MIB/SNMP" statement on the IANA page confuse you.
-OIDs obtained using this form may be used for any purpose including
-identifying LDAP schema elements.
+Note: Don't let the "MIB/SNMP" statement on the IANA page confuse
+you. OIDs obtained using this form may be used for any purpose
+including identifying LDAP schema elements.
+
+Alternatively, OID name space may be available from a national
+authority (e.g., ANSI, BSI).
+
+For private experiments, OIDs under {{EX:1.1}} may be used. The
+OID {{EX:1.1}} arc is regarded as dead name space.
H3: Name Prefix
In addition to assigning a unique object identifier to each schema
element, you should provide a least one textual name for each
-element. The name should be both descriptive and not likely
-to clash with names of other schema elements. In particular,
-any name you choose should not clash with present or future
-Standard Track names.
+element. The name should be both descriptive and not likely to
+clash with names of other schema elements. In particular, any name
+you choose should not clash with present or future Standard Track
+names.
-To reduce (but not eliminate) the potential for name clashes,
-the convention is to prefix names of non-Standard Track with
-a few letters to localize the changes to your organization.
-The smaller the organization, the longer your prefix should
-be.
+To reduce (but not eliminate) the potential for name clashes, the
+convention is to prefix names of non-Standard Track with a few
+letters to localize the changes to your organization. The smaller
+the organization, the longer your prefix should be.
-In the examples below, we have choosen a short prefix '{{EX:my}}'
-(to save space). Such a short prefix would only be suitable for
-a very large, global organization. For a small, local organization,
-we recommend something like '{{EX:deFirm}}' (German company) or
-'{{EX:comExample}}' (elements associated with organization associated
-with {{EX:example.com}}).
+In the examples below, we have chosen a short prefix '{{EX:my}}'
+(to save space). Such a short prefix would only be suitable for a
+very large, global organization. In general, we recommend something
+like '{{EX:deFirm}}' (German company) or '{{EX:comExample}}' (elements
+associated with organization associated with {{EX:example.com}}).
H3: Local schema file
> [ "EQUALITY" woid ; Matching Rule name
> [ "ORDERING" woid ; Matching Rule name
> [ "SUBSTR" woid ] ; Matching Rule name
-> [ "SYNTAX" whsp noidlen whsp ] ; see section 4.3
+> [ "SYNTAX" whsp noidlen whsp ] ; Syntax OID
> [ "SINGLE-VALUE" whsp ] ; default multi-valued
> [ "COLLECTIVE" whsp ] ; default not collective
> [ "NO-USER-MODIFICATION" whsp ]; default user modifiable
>
where whsp is a space ('{{EX: }}'), numericoid is a globally unique
-OID in numeric form (e.g. {{EX:1.2.3}}), qdescrs is one or more
-names, woid is either the name or OID, and noidlen is an optional length
-specifier (e.g {{EX:{10}}}).
+OID in dotted-decimal form (e.g. {{EX:1.1.0}}), qdescrs is one or
+more names, woid is either the name or OID optionally followed
+by a length specifier (e.g {{EX:{10}}}).
For example, the attribute types {{EX:name}} and {{EX:cn}} are defined
in {{F:core.schema}} as:
> attributeType ( 2.5.4.41 NAME 'name'
+> DESC 'name(s) associated with the object'
> EQUALITY caseIgnoreMatch
> SUBSTR caseIgnoreSubstringsMatch
> SYNTAX 1.3.6.1.4.1.1466.115.121.1.15{32768} )
-> attributeType ( 2.5.4.3 NAME
-> ( 'cn' $ 'commonName' ) SUP name )
-
-Notice that each defines the attribute's OID and descriptive
-names. Each name is an alias for the OID. {{slapd}}(8) returns
-the first listed name when returning results.
+> attributeType ( 2.5.4.3 NAME ( 'cn' 'commonName' )
+> DESC 'common name(s) assciated with the object'
+> SUP name )
-The first attribute, {{EX:name}}, has a syntax of {{EX:directoryString}}
-(a UTF-8 encoded Unicode string) with a recommend maximun length.
-Note that syntaxes are specified by OID. In addition, the equality
-and substring matching uses case ignore rules. Below are tables
-listing commonly used supported syntax and matching rules.
+Notice that each defines the attribute's OID, provides a short name,
+and a brief description. Each name is an alias for the OID.
+{{slapd}}(8) returns the first listed name when returning results.
+
+The first attribute, {{EX:name}}, holds values of {{EX:directoryString}}
+(UTF-8 encoded Unicode) syntax. The syntax is specified by OID
+(1.3.6.1.4.1.1466.115.121.1.15 identifies the directoryString
+syntax). A length recommendation of 32768 is specified. Servers
+should support values of this length, but may support longer values
+The field does NOT specify a size constraint, so is ignored on
+servers (such as slapd) which don't impose such size limits. In
+addition, the equality and substring matching uses case ignore
+rules. Below are tables listing commonly used syntax and
+matching rules (OpenLDAP supports these and many more).
!block table; align=Center; coltags="EX,EX,N"; \
- title="Table 6.3: Supported Syntaxes"
+ title="Table 8.3: Commonly Used Syntaxes"
Name OID Description
-binary 1.3.6.1.4.1.1466.115.121.1.5 BER/DER data
boolean 1.3.6.1.4.1.1466.115.121.1.7 boolean value
distinguishedName 1.3.6.1.4.1.1466.115.121.1.12 DN
directoryString 1.3.6.1.4.1.1466.115.121.1.15 UTF-8 string
>
!block table; align=Center; coltags="EX,N"; \
- title="Table 6.4: Supported Matching Rules"
+ title="Table 8.4: Commonly Used Matching Rules"
Name Type Description
booleanMatch equality boolean
+octetStringMatch equality octet string
objectIdentiferMatch equality OID
distinguishedNameMatch equality DN
-uniqueMemberMatch equality DN with optional UID
+uniqueMemberMatch equality Name with optional UID
numericStringMatch equality numerical
numericStringOrderingMatch ordering numerical
numericStringSubstringsMatch substrings numerical
caseExactOrderingMatch ordering case sensitive, space insensitive
caseExactSubstringsMatch substrings case sensitive, space insensitive
caseIgnoreIA5Match equality case insensitive, space insensitive
-caseIgnoreOrderingIA5Match ordering case insensitive, space insensitive
-caseIgnoreSubstringsIA5Match substrings case insensitive, space insensitive
+caseIgnoreIA5OrderingMatch ordering case insensitive, space insensitive
+caseIgnoreIA5SubstringsMatch substrings case insensitive, space insensitive
caseExactIA5Match equality case sensitive, space insensitive
-caseExactOrderingIA5Match ordering case sensitive, space insensitive
-caseExactSubstringsIA5Match substrings case sensitive, space insensitive
+caseExactIA5OrderingMatch ordering case sensitive, space insensitive
+caseExactIA5SubstringsMatch substrings case sensitive, space insensitive
!endblock
The second attribute, {{EX:cn}}, is a subtype of {{EX:name}} hence
it inherits the syntax, matching rules, and usage of {{EX:name}}.
{{EX:commonName}} is an alternative name.
-Neither attribute is restricted to a single value and both are
-meant for usage by user applications. You likely won't need to
-specify other parameters such as {{EX:OBSOLETE}}.
+Neither attribute is restricted to a single value. Both are meant
+for usage by user applications. Neither is obsolete nor collective.
The following subsections provide a couple of examples.
> SYNTAX 1.3.6.1.4.1.1466.115.121.1.40
> SINGLE-VALUE )
-As noted in the description, LDAP has no knowledge of the
-format of the photo. It's assumed that all applications
-accessing this attribute agree on the handling of values.
+In this case, the syntax doesn't specify the format of the photo.
+It's assumed (maybe incorrectly) that all applications accessing
+this attribute agree on the handling of values.
If you wanted to support multiple photo formats, you could define
a separate attribute type for each format, prefix the photo
Another alternative is for the attribute to hold a {{TERM:URI}}
pointing to the photo. You can model such an attribute after
-{{EX:labeledURI}} ({{REF:RFC2079}}).
+{{EX:labeledURI}} ({{REF:RFC2079}}) or simply create a subtype,
+e.g.:
+
+> attributetype ( 1.1.2.1.3 NAME 'myPhotoURI'
+> DESC 'URI and optional label referring to a photo'
+> SUP labeledURI )
H3: Object Class Specification
> whsp ")"
where whsp is a space ('{{EX: }}'), numericoid is a globally unique
-OID in numeric form (e.g. {{EX:1.2.3}}), qdescrs is one or more
+OID in numeric form (e.g. {{EX:1.1.0}}), qdescrs is one or more
names, and oids is one or more names and/or OIDs.
> objectclass ( 1.1.2.2.2 NAME 'myPerson'
> DESC 'my person'
> SUP inetOrgPerson
-> MUST ( 'myUniqueName' $ 'givenName' )
-> MAY 'myPhoto' )
+> MUST ( myUniqueName $ givenName )
+> MAY myPhoto )
The object class inherits the required/allowed attribute
types of {{EX:inetOrgPerson}} but requires {{EX:myUniqueName}}
{{slapd}}(8).
LDAPv3 servers publish schema elements in special {{subschema}}
-entries (or subentries). {{slapd}}(8) publishes a single subschema
-entry normally named {{EX:cn=Subschema}}. If a server which
-supports a single subschema subentry, the DN of the subschema
-subenty can usually be found by examining the value of the
-{{EX:subschemaSubentry}} attribute type in the {{root DSE}}
-Other servers may publish multiple subschema entries. These
-can be located by examining the {{EX:subschemaSubentry}} attribute
-contained in the entry at the root of each administrative context.
+entries (or subentries). While {{slapd}}(8) publishes a single
+subschema subentry normally named {{EX:cn=Subschema}}, this behavior
+cannot be expected from other servers. The subschema subentry
+controlling a particular entry can be obtained by examining the
+{{EX:subschemaSubentry}} attribute contained in the entry at the
+root of each administrative context. For example,
+
+> ldapsearch -LLL -x -b "dc=example,dc=com" -s base "(objectclass=*)" subschemaSubentry
To obtain the schema from a subschema subentry, you can use
ldapsearch(1) as follows (replace the search base as needed):
> ldapsearch -LLL -x -b "cn=Subschema" -s base "(objectclass=subschema)" attributeTypes objectClasses
+where "cn=Subschema" is the value of subschemaSubentry returned in
+the prior search.
+
This will return {{TERM:LDIF}} output containing many type/value
pairs. The following is an abbreviated example:
> dn: cn=Subschema
+> objectClasses: ( 1.1.2.2.2 NAME 'myPerson' DESC 'my person' SUP inet
+> OrgPerson MUST ( myUniqueName $ givenName ) MAY myPhoto )
> attributeTypes: ( 1.1.2.1.1 NAME 'myUniqueName' DESC 'unique name wi
> th my organization' EQUALITY caseIgnoreMatch SUBSTR caseIgnoreSubst
> ringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 SINGLE-VALUE )
> attributeTypes: ( 1.1.2.1.2 NAME 'myPhoto' DESC 'a photo (applicatio
> n defined format)' SYNTAX 1.3.6.1.4.1.1466.115.121.1.40
-> objectClasses: ( 1.1.2.2.2 NAME 'myPerson' DESC 'my person' SUP inet
-> OrgPerson MUST ( 'myUniqueName' $ 'givenName' ) MAY 'myPhoto' )
Capture the output of the search in a file and then edit the file:
+ to contain only desired type/value pairs
^ join LDIF continuation lines
^ replace attribute type with directive name
-(e.g. {{EX:s/attributeTypes:/attributeType/}} and
-{{EX:s/objectClasses:/objectClass/}}).
+(e.g. {{EX:s/attributeTypes:/attributeType /}} and
+{{EX:s/objectClasses:/objectClass /}}).
+^ reorder lines so each element is defined before first use
^ continue long directives over multiple lines
For the three type/value pairs in our example, the edit should
> objectClass ( 1.1.2.2.2 NAME 'myPerson'
> DESC 'my person'
> SUP inetOrgPerson
-> MUST ( 'myUniqueName' $ 'givenName' )
-> MAY 'myPhoto' )
+> MUST ( myUniqueName $ givenName )
+> MAY myPhoto )
-Save in an appropriately named file (e.g. {{F:my.schema}}).
-You may now include this file in your {{slapd.conf}}(8) file.
+Save in an appropriately named file (e.g. {{F:local.schema}}).
+You may now include this file in your {{slapd.conf}}(5) file.
!endif
+
+
+H3: OID Macros
+
+To ease the management and use of OIDs, {{slapd}}(8) supports
+{{Object Identifier}} macros. The {{EX:objectIdentifier}} directive
+is used to equate a macro (name) with a OID. The OID may possibly
+be derived from a previously defined OID macro. The {{slapd.conf}}(5)
+syntax is:
+
+E: objectIdentifier <name> { <oid> | <name>[:<suffix>] }
+
+The following demonstrates definition of a set of OID macros
+and their use in defining schema elements:
+
+> objectIdentifier myOID 1.1
+> objectIdentifier mySNMP myOID:1
+> objectIdentifier myLDAP myOID:2
+> objectIdentifier myAttributeType myLDAP:1
+> objectIdentifier myObjectClass myLDAP:2
+> attributetype ( myAttributeType:3 NAME 'myPhotoURI'
+> DESC 'URI and optional label referring to a photo'
+> SUP labeledURI )
+> objectclass ( myObjectClass:1 NAME 'myPhotoObject'
+> DESC 'mixin myPhoto'
+> AUXILIARY
+> MAY myPhoto )
+
projects / openldap / blobdiff