On Wed, 7 Apr 2010 10:15:14 -0400 "Michael Bayer" <mike...@zzzcomputing.com> wrote:
> Kyle Schaffrick wrote: > > Greetings, > > > > I'm looking into using PostgreSQL's hstore type in a SQLAlchemy > > project, and before I possibly reinvent the wheel I was wondering if > > anyone has/knows of an implementation of an hstore custom type for > > SQLA? > > > > I'm basically just interested in simply mapping a stand-alone > > attribute containing a python dict onto an hstore column, I don't > > require auto-magic storage of extra attributes directly added to > > the object a la examples/vertical. > > > > Mainly I want the hstore segregated into it's own attribute because > > I'd like to be able to expose expression language support for > > hstore's operators (?, ->, ||, and so forth) to manipulate them > > server-side. > > > > Any pointers? > > start with 0.6, as we've expanded the capability for types to directly > affect how various operators are rendered, as well as to drive the > return type of expressions, which in turn allows that expression to > have a say in its own usage in another expression, as well as affects > result row behavior. > I had planned on using 0.6 just to get the benefit of the new dialect+dbapi system. I did see the @compiles() idiom in some example code, is this what you're referring to? It looks like a great new feature. Have there been any thoughts on user-extensible reflection? Some way to say "when you reflect a DB column of type foo, use this custom type class"? If I got the right impression from skimming, dispatching reflected types is essentially a big cascade of if-statements at the moment. I don't really know how many DBMS's in SA's arsenal have extensible type systems, so not sure if it's worth the trouble. I assume you can just override column information piecemeal without having to give up reflection of columns with vanilla types. > if hstore represents a python value that is "mutable" (which a dict > would be), mixing in MutableType will cause the ORM to maintain a > copy of the original version of the attribute in order to check for > changes. > Good information, thanks. I can see why this would need to be handled specially. -Kyle -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalch...@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
