Maintaining Consistent SchemaChapter 3 How to Design the Schema 53that attributes that are not 'user defined' will appear in the read-onlysection of the Directory Server Console, and you will not be able to use theconsole to edit object classes that contain an X-ORIGIN other than 'userdefined'.Using an X-ORIGIN of value 'user defined' ensures that schema definitions inthe 99user.ldif file are not removed from the file by the directory. The directorydoes not remove them because it relies on an X-ORIGIN of 'user defined' to tell itwhat elements should reside in the 99user.ldif file.For example, you create a schema entry manually in 99user.ldif as follows:attributetypes: ( exampleContact-oid NAME 'exampleContact' DESC'Example Corporate contact' SYNTAX1.3.6.1.4.1.1466.115.121.1.15X-ORIGIN 'Example defined')After the directory loads the schema entry, it appears as follows:attributetypes: ( exampleContact-oid NAME 'exampleContact' DESC'Example Corporate contact' SYNTAX1.3.6.1.4.1.1466.115.121.1.15X-ORIGIN ('Example defined' 'user defined') )• When adding new schema elements, all attributes need to be defined beforethey can be used in an object class. You can define attributes and object classesin the same schema file.• Each custom attribute or object class you create should be defined in only oneschema file. This prevents the server from overriding any previous definitionswhen it loads the most recently created schema (as the server loads the schemain numerical order first, then alphabetical order).Maintaining Consistent SchemaA consistent schema within Directory Server aids LDAP client applications inlocating directory entries. If you use an inconsistent schema, then it becomes verydifficult to locate information in your directory tree efficiently.Inconsistent schema use different attributes or formats to store the sameinformation. You can maintain schema consistency in the following ways:• Use schema checking to ensure attributes and object classes conform to theschema rules.• Select and apply a consistent data format.
