Hi, I have an issue while refactoring the schema. I want to have your opinion about it. RFC 4512 states that : " 2.5.1. Attribute Types An attribute type governs whether the attribute can have multiple values, the syntax and matching rules used to construct and compare values of that attribute, and other functions. The attribute type indicates whether the attribute is a user attribute or an operational attribute. If operational, the attribute type indicates the operational usage and whether or not the attribute is modifiable by users. Operational attributes are discussed in Section 3.4. An attribute type (a subtype) may derive from a more generic attribute type (a direct supertype). The following restrictions apply to subtyping: - a subtype must have the same usage as its direct supertype,..." In our case, we have 5 AT which inherit from distinguishedName or Name, which is a User attrinuteType, and have another Usage : apacheAlias(distinguishedName), autonomousAreaSubentry(distinguishedName), apacheExistence (name), accessControlSubentries(distinguishedName), triggerExecutionSubentries(distinguishedName) I don't think they should inherit from any other AT, IMO. WDYT ? -- Regards, Cordialement, Emmanuel Lécharny www.iktek.com