The IBMAttributeTypes attribute

The IBMAttributeTypes attribute can be used to define schema information not covered by the LDAP Version 3 standard for attributes. Values of IBMAttributeTypes must comply with the following grammar:

IBMAttributeTypesDescription = "(" whsp
        numericoid whsp
      [ "DBNAME"   qdescrs ]            ; at most 2 names (table, column)
      [ "ACCESS-CLASS" whsp IBMAccessClass whsp ]
      [ "LENGTH" wlen whsp ]            ; maximum length of attribute
      [ "EQUALITY" [ IBMwlen ] whsp ]   ; create index for matching rule
      [ "ORDERING" [ IBMwlen ] whsp ]   ; create index for matching rule
      [ "APPROX"   [ IBMwlen ] whsp ]   ; create index for matching rule
      [ "SUBSTR"   [ IBMwlen ] whsp ]   ; create index for matching rule
      [ "REVERSE"  [ IBMwlen ] whsp ]   ; reverse index for substring
      whsp ")"

   IBMAccessClass =
      "NORMAL"            / ; this is the default
      "SENSITIVE"         /
      "CRITICAL"          /
      "RESTRICTED"        /
      "SYSTEM"            /
      "OBJECT"

   IBMwlen = whsp len
 

Numericoid

Used to correlate the value in attributetypes with the value in IBMAttributeTypes.

DBNAME

You can provide 2 names at the most, if indeed 2 names are given. The first is the table name used for this attribute. The second is the column name used for the fully normalized value of the attribute in the table. If you provide only one name, it is used as the table name as well as the column name. If you do not provide any DBNAMEs, then a name based on the first seventeen characters of the attribute name (which must be unique) is used. Database table and column names are limited to seventeen characters.

ACCESS-CLASS

The access classification for this attribute type. If ACCESS-CLASS is omitted, it defaults to normal.

LENGTH

The maximum length of this attribute. The length is expressed as the number of bytes. Directory Server has a provision for specifying the length of an attribute. In the attributetypes value, the string:

( attr-oid ... SYNTAX syntax-oid{len} ... )

can be used to indicate that the attributetype with oid attr-oid has a maximum length.

EQUALITY, ORDERING, APPROX, SUBSTR, REVERSE

If any of these attributes are used, an index is created for the corresponding matching rule. The optional length specifies the width of the indexed column. A single index is used to implement multiple matching rules. The Directory Server assigns a length of 500 when one is not provided by the user. The server can also use a shorter length than what the user requested when it makes sense to do so. For example, when the length of the index exceeds the maximum length of the attribute, the index length is ignored.