When a database is opened in shared mode(which it does when working with a website), it's necessary to address issues of concurrency, that is, the simultaneous availability of the same sets of data and objects to multiple users. This is done through a locking information file (.ldb), which stores information about any records that are locked in a shared database.
When the first user opens a database in shared mode, the Jet database engine automatically creates a locking information file in the same folder as the database. The Jet database engine then uses this same locking file to manage locking for each subsequent user who opens the same database. One locking information file is created for each Access database (.mdb) that is opened in shared mode. The Jet database engine gives the file the same name as the database that was opened, but with an .ldb file name extension. The Jet database engine deletes the .ldb file for a database when the last user closes the database.
For more information about the locking information file and Jet database engine locking architecture, see "Introduction to Microsoft Jet Locking", which is available in the Microsoft Office Developer Web site at