hey matt - you might also look at a new feature we have in 0.4 called "composite column types", this is an ORM-only feature whereby you can provide column-behavior on a plugin basis and also use multiple columns to represent a single scalar unit:
http://www.sqlalchemy.org/docs/04/mappers.html#advdatamapping_mapper_composite On Aug 9, 6:04 pm, mattrussell <[EMAIL PROTECTED]> wrote: > Hi Michael, > I've sorted this one now :) > I'm sorry for the amigious nature of my post... wasn't clear in my > head at the time. > You are right, I wasn't associating between the two entities in the > example I gave. > I ended up using sqlalchemy.sql._BinaryExpresssion in my subclass, > which enabled the behavior i sought. > I'm using a bleeding edge combination of elixir, tesla and sa, so > won't elaborate more here, otherwise it'd take a while and a > considerable space! > If you're intersted, I can show you how I've achieved geometry support > using elixir and sa via pm or email. > > Thanks, > Matt > > On Aug 9, 4:44 pm, Michael Bayer <[EMAIL PROTECTED]> wrote: > > > add_entity() by itself is not going to add a table to a count() > > function; the extra entities arent taken into account by count(). > > Looking at the query you have below, i.e. the one which "works", im a > > little puzzled. you aren't associating the geo_route and > > geo_location tables together at all. so...you actually just want to > > multiply geo_route rows times geo_location rows ? > > > anyway, to add a FROM clause explicitly, use query.select_from > > (geo_location), and the table will be added to the FROM clause. > > > On Aug 9, 2007, at 10:23 AM, mattrussell wrote: > > > > Hi, related to my recent post on subclassing Column: > > > > The problem I have is that the right tables are not appearing in the > > > "FROM" list in the query. > > > I have overriden the 'in_' operatror on the column. > > > > When calling 'all()' on my query instance, I get the result back as I > > > expected, but when calling 'count()' a table is missing which is used > > > in the where clause: > > > > This is an example of a query which works using the 'count()' > > > function on my query object: > > > > 2007-08-07 19:42:43,082 INFO sqlalchemy.engine.base.Engine.0x..8c > > > SELECT count(geo_route.id) > > > FROM geo_route, geo_location > > > WHERE geo_location.id IN (%(geo_location_id)s, %(geo_location_id_1)s) > > > > And this is the one produced with my Column subclass overrindg 'in_' > > > in place. > > > Whether or not it overrides 'in_' or uses a different name ('within' > > > for example) is irrelevent here i think. > > > SELECT count(geo_route.id) \nFROM geo_route \nWHERE geo_location.point > > > && SetSRID('BOX3D(-74.847708 39.884318, -74.823589 39.904667)'::box3d, > > > 4326)" {} > > > > What am I missing? I assume operators do something to add the correct > > > columns to the FROM list, but I can't see where. I've added print > > > statements to the SA source to that end, but haven't been able to see > > > it. > > > > Any help much appriciated. > > > > Thanks, > > > Matt --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
