On Mon, Sep 12, 2011 at 11:20 PM, Chris Clark <chris.cl...@ingres.com> wrote:
> I was discussing with someone today autocommit support and found an area of > pep-249 where I think we could improve the wording (and the spec): Agreed, it would have been long due. The quick survey I did when we introduced the session in psycopg (last May) has been: - MySQLdb: conn.autocommit() - cx_Oracle: conn.autocommit (attribute, not function) - pyodbc: conn.autocommit (attribute) - sqlite3: conn.isolation_level = None - KInterbaseDB: not supported (to give context, in psycopg you had to use conn.set_isolation_level(0) before version 2.4.2, when we introduced better ways to manipulate the session - see <http://archives.postgresql.org/psycopg/2011-05/msg00026.php> for the discussion. Psycopg now uses an autocommit attribute - see <http://initd.org/psycopg/docs/connection.html#connection.autocommit>). > To get the ball rolling, here is an initial suggestion: > > * needs to take a boolean flag as a parameter to enable and also disable > * needs to return the auto commit state so it can be queried [thus] > autocommit(on=None) > returns True when autocommit is on, and False when autocommit is off. > If the keyword parameter "on" is set to True, the connection will > commit any open transactions (as if connection.commit() was issued) and all > subsequent transactions will auto commit, the method returns True if > successfully in autocommit mode. > If the keyword parameter "on" is set to False, the connection will > commit any open transactions (as if connection.commit() was issued) and all > subsequent transactions will no longer auto commit, the method returns False > if successfully out of autocommit mode.. Because you need a getter and a setter, I feel the right solution is to use a property. A function that behaves as a getter when called with no parameter and as a setter if it has one is not something widely used in pythonland. A more natural solution, but inferior, would be using two functions (of which choosing the name is a bikeshedding bloodbath). Properties are just the right tools for this task, and appear to be the most used solution in popular drivers. The behaviour of setting autocommit when a transaction is already open is also to be seen: there are three basic option: - have a commit - have a rollback - have an error I feel the implicit commit is the most dangerous option. An implicit rollback may be more acceptable (it's the same behaviour of closing the connection with a transaction in progress): I proposed it for psycopg but, in the discussion, raising an exception proved the most popular option. -- Daniele _______________________________________________ DB-SIG maillist - DB-SIG@python.org http://mail.python.org/mailman/listinfo/db-sig
