On 26.03.2014 20:38, Tony Locke wrote: > Hi Daniele, the latest release of pg8000 (1.9.7) has (experimental) > support for prepared statements, but takes an implicit approach rather > than an explicit one. In the connect() function there's a boolean > use_cache parameter which tells pg8000 to cache prepared statements, > keyed against the SQL query string. So when you do: > > cursor.execute(sql_query, params) > > it does a lookup on sql_query in a local cache, and executes the > prepared statement if one is found, or creates and caches a new one if > not. This implicit approach means that no extension to the DB-API is > needed.
Hi Tony, thanks for the feedback. Please note that one of the main reasons for having a separate explicit API to prepare a statement is to run the query parser on the statement (and prepare the query plan on the server) without actually executing the statement. This can be used to e.g. setup a pool of cursors with already prepared statements for faster execution of commonly used queries. Your approach implements the standard caching mechanism that is already documented in the DB-API. It only extend this by caching not only the last statement, but a set of statements, if I understand correctly. The pool creation is also possible with this approach, but only after the cursors were used at last once. I don't think the use case is important enough to make .prepare() a requirement in the DB-API, but it would be great if we could come up with a standard extension definition. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, Mar 27 2014) >>> Python Projects, Consulting and Support ... http://www.egenix.com/ >>> mxODBC.Zope/Plone.Database.Adapter ... http://zope.egenix.com/ >>> mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/ ________________________________________________________________________ 2014-03-29: PythonCamp 2014, Cologne, Germany ... 2 days to go 2014-04-09: PyCon 2014, Montreal, Canada ... 13 days to go 2014-04-29: Python Meeting Duesseldorf ... 33 days to go eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 http://www.egenix.com/company/contact/ _______________________________________________ DB-SIG maillist - DB-SIG@python.org https://mail.python.org/mailman/listinfo/db-sig
