On 3/26/07, Michael Bayer <[EMAIL PROTECTED]> wrote:
>
> > (and whether that be a .query() or Query() or SelectResults not big
> > difference imo.)
> >
>
> i vote Query().
I tried to implement it but I couldn't do it the way I wanted to. The
problem is: how do I construct a clause from a clause with bind
parameters + a dictionary containing the values for said bind
parameters? I've only seen bind parameters resolved at execution time.
Is it possible to resolve them earlier? In the attached patch, I used
a workaround which is to store the bind parameters in the query
itself, and then use them whenever the query is executed.
Two remarks:
* I've implemented Query.from_attr, instead of adding new keywords to
the Query "constructor", because I think:
Query.from_attr(someuser, 'addresses')
looks better, is shorter and is more readable than:
Query('Address', instance=someuser, attr_name='addresses')
* It only works for lazy attributes. I don't think there is any reason
we couldn't make it work for eager attributes, but by looking at the
eagerloader code, I couldn't figure how to do it.
--
Gaëtan de Menten
http://openhex.org
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Index: orm/query.py
===================================================================
--- orm/query.py (revision 2444)
+++ orm/query.py (working copy)
@@ -42,12 +42,32 @@
self._distinct = kwargs.pop('distinct', False)
self._offset = kwargs.pop('offset', None)
self._limit = kwargs.pop('limit', None)
- self._criterion = None
+ self._criterion = kwargs.pop('criterion', None)
+ self._params = kwargs.pop('params', {})
self._joinpoint = self.mapper
self._from_obj = [self.table]
for opt in util.flatten_iterator(self.with_options):
opt.process_query(self)
+
+ def from_attr(cls, instance, attr_name):
+ prop = instance.mapper.props[attr_name]
+ loader = prop.strategy
+ #TODO: make it work for eager loader too.
+ # code taken from strategies.py
+ params = {}
+ allparams = True
+ for col, bind in loader.lazybinds.iteritems():
+ params[bind.key] = loader.parent.get_attr_by_column(instance, col)
+ if params[bind.key] is None:
+ allparams = False
+ break
+
+ if not allparams:
+ return None
+
+ return Query(prop.mapper, criterion=loader.lazywhere, params=params)
+ from_attr = classmethod(from_attr)
def _clone(self):
q = Query.__new__(Query)
@@ -71,6 +91,7 @@
q._from_obj = list(self._from_obj)
q._joinpoint = self._joinpoint
q._criterion = self._criterion
+ q._params = self._params
return q
def _get_session(self):
@@ -690,8 +711,10 @@
method, which takes the executed statement's ResultProxy
directly.
"""
-
- result = self.session.execute(self.mapper, clauseelement,
params=params)
+ final_params = self._params.copy()
+ if params is not None:
+ final_params.update(params)
+ result = self.session.execute(self.mapper, clauseelement,
params=final_params)
try:
return self.instances(result, **kwargs)
finally:
