A method, system and apparatus for managing variable information in a line information database (LIDB). In summary, a LIDB which has been configured in accordance with the present invention and which further has been disposed within a public switched telephone network (PSTN) can include a first collection of invariant data persisted in individual records in the LIDB. Each of the records can have an association with a subscriber in the PSTN. A second collection of variable data can be persisted in the individual records in the LIDB. Specifically, the variable data can have been produced in an application deployed outside of the PSTN in a data communications network. Finally, a query interface can be included in the LIDB (or in association with the LIDB) to retrieve the variable data therein and to persist variable data therein.