Which directory should be writable to update wordpress?

Tetsu, the Codex has some good insights on this:

http://codex.wordpress.org/Changing_File_Permissions

Unfortunately there is no ‘one size fits all’ according to the Codex. It may depend on your host.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)