changeAccessMode

changeAccessMode(mode: Integer);

The changeAccessMode method of the DbFile class changes the access mode of the file from read-only (Mode_ReadOnly) to update (Mode_Update), or the reverse. Use this method to allow applications to compact database files without shutting down the database. This method executes on a persistent server node, and is implemented and executed by the physical database engine.

When a file is changed to read-only mode, any threads that attempt to start a new transaction are first blocked, waiting for pending transactions to complete. All dirty buffers for objects resident in the file are flushed and the file is locked against further updates. At this point, threads blocked by the beginTransaction instruction are allowed to continue.

Any database operations that attempt to update a file in read-only mode receive an exception.