On Thu, Nov 7, 2013 at 4:31 PM, L. Wood <lwoo...@live.com> wrote: > Users could rename/move a database file while my (Mac OS X) program has made > an SQLite connection to the file. I want to handle this properly.
One thing you have to be particularly careful about is the extra files sqlite creates next to the database file, such as the rollback journal files. The page http://sqlite.org/tempfiles.html documents how sqlite currently uses these. In particular, if sqlite finds the database file but does not file the associated journal file, your database can go corrupted. I don't know how you could assure that this does not happen. Instead of trying to handle errors from the frontend of sqlite, you might get a more robust solution if you wrote a custom VFS backend for sqlite, possibly by modifying the existing uniq VSF backend. The VFS is documented on http://sqlite.org/vfs.html . Sqlite performs all operating system dependent functions through the replacable VFS backend. These operations include opening a file, reading, writing, file locking. This way if, for example, if you detect that a user have moved the database file and sqlite wants to open the corresponding rollback journal file, you can make sure that it opens the correct rollback journal. Besides ensuring that there the extra files are found correctly, you will also have to make sure that file locking works correctly accross moves. All this gets quite complicated (maybe even impossible), especially if multiple programs want to open the same sqlite database concurrently. Ambrus _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
