Data processing system and method for multi-level directory searches

An apparatus and method for performing a multi-level directory search are implemented. The directory information may be stored in a backing store in accordance with a relational database. An ancestor table is generated which maps each node in the directory which is an ancestor of one or more descendant nodes to each of its ancestor nodes. Each node is associated with a unique identifier, which may be used to relate ancestor and descendant nodes. The table includes the identifier of each ancestor in association with all the corresponding descendants. Additionally, the table maps the distance between the ancestor and each descendant. For a search initiated at a given node the distance values may be used to delimit a search in accordance with a specified search scope. The search scope may be specified as a parameter in a Lightweight Directory Access Protocol (LDAP) search request.