reread your example code, that will actually do the trick.
On Wednesday, March 26, 2014 9:07:52 AM UTC-4, Michael Robellard wrote:
>
> I want it mapped to an object because I want to have some
> properties/methods that can be executed on each row of the results that
> will do some additional logic.
>
> On Tuesday, March 25, 2014 6:21:31 PM UTC-4, Michael Bayer wrote:
>>
>>
>> On Mar 25, 2014, at 2:43 PM, Michael Robellard <mi...@robellard.com>
>> wrote:
>>
>> > Hello, I have what seems like a simple problem, but the only solution I
>> have come up with so far isn't very good. I have a large complex query that
>> is hand optimized that is built from aggregates and other data from
>> different mapped tables. I can create a query for it by doing
>> Session.query([column names]).from_statement(query).params({}) and that
>> works just fine, but rather than each row being a KeyedTuple, I would like
>> each row to be mapped to an object of a class, so that I can create some
>> properties and methods on the object
>> >
>> > When I tried
>> http://docs.sqlalchemy.org/en/rel_0_9/orm/mapper_config.html#mapping-a-class-against-arbitrary-selectsI
>> get an error about not having a primary key defined
>> >
>> > I did get this to kind of work with Bundles, but it looks ugly and you
>> have to dereference the bundle
>> >
>> > Here's a gist of the code:
>> https://gist.github.com/subssn21/0f7300203aa39536ff5d
>> >
>> > What's the right way to handle this?
>>
>> the query you have there is entirely fixed. You can map to this if you
>> wanted (using mapper() with text()) but as this is read only and has no
>> malleability at all, you might as well just map a dictionary to it:
>>
>> class ShiftPunchData(object):
>> def some_method(self):
>> pass
>>
>> @classmethod
>> def load_data(cls, session):
>> for row in session.execute(“ your big query goes here”):
>> s = ShiftPunchData()
>> s.__dict__.update(row)
>> yield s
>>
>> you’d get the same effect. of course theres no relationships or eager
>> loading or anything like that but you’re working with an enormous fixed
>> query so none of that applies anyway.
>>
>> now if OTOH you want to build a flexible mapping based on that general
>> query idea, you’d want to express most or all of it in terms of a SQL
>> expression, either a core expression or ORM. It depends on what you want
>> to be able to do with it.
>>
>>
>>
>>
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