The flags correspond to those for the open() system call. (Typically 0 means read-only, 1 means write-only, and 2 means read and write.)
Returns a dbase_identifier for the opened database, or FALSE if the database couldn't be opened.
Note: When safe mode is enabled, PHP checks whether the file(s)/directories you are about to operate on have the same UID as the script that is being executed.