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Mike Bayer
b2e04755cc
into a new set of methods available off of Query. These methods
all provide "generative" behavior, whereby the Query is copied
and a new one returned with additional criterion added.
The new methods include:
filter() - applies select criterion to the query
filter_by() - applies "by"-style criterion to the query
avg() - return the avg() function on the given column
join() - join to a property (or across a list of properties)
outerjoin() - like join() but uses LEFT OUTER JOIN
limit()/offset() - apply LIMIT/OFFSET
range-based access which applies limit/offset:
session.query(Foo)[3:5]
distinct() - apply DISTINCT
list() - evaluate the criterion and return results
no incompatible changes have been made to Query's API and no methods
have been deprecated. Existing methods like select(), select_by(),
get(), get_by() all execute the query at once and return results
like they always did. join_to()/join_via() are still there although
the generative join()/outerjoin() methods are easier to use.
- the return value for multiple mappers used with instances() now returns
a cartesian product of the requested list of mappers, represented
as a list of tuples. this corresponds to the documented behavior.
So that instances match up properly, the "uniquing" is disabled when
this feature is used.
- strings and columns can also be sent to the *args of instances() where
those exact result columns will be part of the result tuples.
- query() method is added by assignmapper. this helps with
navigating to all the new generative methods on Query.