HP-UX Directory Server 8.1 schema reference

1.1.2.2 Single- and multivalued attributes
By default, most attributes are multivalued. This means that an entry can contain the same
attribute multiple times, with different values. For example:
dn: uid=jsmith, ou=marketing, ou=people, dc=example, dc=com
ou: marketing
ou: people
The cn, tel, and objectclass attributes, for example, all can have more than one value.
Attributes that are single-valued (that is, only one instance of the attribute can be specified) are
specified in the schema as only allowing a single value. For example, uidNumber can only have
one possible value, so its schema entry has the term SINGLE-VALUE. If the attribute is
multivalued, there is no value expression.
1.2 Default Directory Server schema files
The default schema definitions for Directory Server are stored in the /etc/opt/dirsrv/schema
directory. These default schema files are used as schema templates for new Directory Server
instances. Each server instance has its own schema directory in
/etc/opt/dirsrv/slapd-instance_name/schema, with the schema files used specifically
by that instance.
To modify the directory schema, create new attributes and new object classes in the
instance-specific schema directory. Because the default schema is used for creating new instances
and each individual instance has its own schema files, it is possible to have slightly different
schema for each instance, matching the use of each instance.
Any custom attributes added using the Directory Server Console or LDAP commands are stored
in the 99user.ldif file; other custom schema files can be added to the
/etc/opt/dirsrv/slapd-instance_name/schema directory for each instance. Do not
make any modifications with the standard files that come with the HP-UX Directory Server.
For more information about how the Directory Server stores information and suggestions for
planning directory schema, see the HP-UX Directory Server deployment guide.
Table 1-2 Schema files
PurposeSchema file
Recommended core schema from the X.500 and LDAP standards (RFCs) and schema used
by the Directory Server itself.
00core.ldif
Standard-related schema from RFC 2256 and LDAPv3 and standard schema defined by
Directory Server itself.
01common.ldif
Schema from RFC 2247 and related pilot schema, defined in "Using Domains in LDAP/X.500
Distinguished Names."
05rfc2247.ldif
Schema from RFC 2927, "MIME Directory Profile for LDAP Schema."05rfc2927.ldif
Schema from RFC 2307, "An Approach for Using LDAP as a Network Information Service."10rfc2307.ldif
Schema for presence information; the file lists the default object classes with the allowed
attributes that must be added to a user's entry in order for instant-messaging presence
information to be available for that user.
10presence.ldif
Common schema element for Directory Server-Nortel subscriber interoperability.20subscriber.ldif
Schema from RFC 2713, "Schema for Representing Java Objects in an LDAP Directory."25java-object.ldif
Schema from the pilot RFCs, especially RFC 1274, that are no longer recommended for use
in new deployments.
28pilot.ldif
Common schema.30ns-common.ldif
Schemas used by the Administration Server.50ns-admin.ldif
12 About Directory Server schema