A method and apparatus for addressing problems associated with the implementation of directory services, such as X.500 and LDAP, in a SQL environment, particularly problems associated with interrogating database provided to implement directory services in the SQL environment. According to the disclosed method and apparatus, the system is based on the use of tables that may be arranged to have a plurality of columns, so that they support a variety of functions in order to implement directory services, such as X.500 and LDAP. In one aspect, the present invention provides a method of creating one or more SQL commands corresponding to a directory service. In another aspect, the present invention provides a many examples of tables and their function. Many examples of an implementation of directory services using SQL based technology are disclosed.