Thank you, I haven't started using hstore in my production environment
yet, but wanted to do some tests with it as a way for users to attach
arbitrary key/value metadata to nodes. Are you currently using a
Gin or Gist index on your hstore columns?
Yes, actually I've got a pretty good start on it. The only obvious
thing missing right now is a Comparator implementation so that the
custom hstore operations are available to mapped classes and not just
to the SQL expression language.
I did want to have access to hstore operations outside of mapped
classes (i.e. just using SQL expression language) so I ended up
implementing it slightly differently than I had originally thought. It
required some hacks which I'm not sure how to do better.
Some thoughts...
1. While you can override existing operators that work on ColumnElements
without doing much funny business, if you want to add *new* operations
to it, the abstractions leak fairly badly. This seems to be because
operator definitions aren't delegated to the class representing the
type, which is suboptimal because I would think that the type of a
ColumnElement is what logically "defines" what operations are valid on
it. The result of this is that I have to create classes like
HStoreColumn, HStoreColumnElement, _HStoreDeleteFunction, and so on, so
that SQL expressions which are logically of type 'hstore' will have the
extended hstore operations available.
2. That expression operations on Foo.some_col and foo_table.c.some_col
take completely different paths in the implementation was slightly
surprising. I would have expected the former to be implemented in terms
of the latter, so that SQL expressions available on some column type are
automatically available on the descriptor of a class which maps to that
column. But I don't know, there might be good reasons for this. In any
case I'm trying to figure out how to write my Comparator for hstore
without repeating myself a lot.
Current implementation attached, with really hacky tests at the end :)
Comments welcome.
-Kyle
--
David Gardner
Pipeline Tools Programmer
Jim Henson Creature Shop
dgard...@creatureshop.com
--
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.
