as the attribute and probably just replaced itself, so that is
now _set_enable_single_crit
- as a side effect of the main issue fixed here, correct the case in
adjust_for_single_inheritance where the same mapper appears more
than once in mapper_adapter_map; run through a set() for uniqueness.
- Fixed bug in subquery eager loading in conjunction with
:func:`.with_polymorphic`, the targeting of entities and columns
in the subquery load has been made more accurate with respect
to this type of entity and others. Fixes#3106
eager loads across a polymorphic-subclass boundary in conjunction
with polymorphic loading would fail to locate the subclass-link in the
chain, erroring out with a missing property name on an
:class:`.AliasedClass`. fixes#3055
the query runs after the loading process has begun; this is so that
the subqueryload takes precedence over other loaders that may be
hitting the same attribute due to other eager/noload situations
at the wrong time. [ticket:2887]
This enables the subquery eager loader strategy to apply a DISTINCT
to the innermost SELECT subquery, to assist in the case where
duplicate rows are generated by the innermost query which corresponds
to this relationship (there's not yet a general solution to the issue
of dupe rows within subquery eager loading, however, when joins outside
of the innermost subquery produce dupes). When the flag
is set to ``True``, the DISTINCT is rendered unconditionally, and when
it is set to ``None``, DISTINCT is rendered if the innermost relationship
targets columns that do not comprise a full primary key.
The option defaults to False in 0.8 (e.g. off by default in all cases),
None in 0.9 (e.g. automatic by default). Thanks to Alexander Koval
for help with this. [ticket:2836]
``query(SubClass).options(subqueryload(Baseclass.attrname))``,
where ``SubClass`` is a joined inh of ``BaseClass``,
would fail to apply the ``JOIN`` inside the subquery
on the attribute load, producing a cartesian product.
The populated results still tended to be correct as additional
rows are just ignored, so this issue may be present as a
performance degradation in applications that are
otherwise working correctly. [ticket:2699]
- paths now store Mapper + MapperProperty now instead of string key,
so that the parent mapper for the property is known, supports same-named
properties on multiple subclasses
- the Mapper within the path is now always relevant to the property
to the right of it. PathRegistry does the translation now, instead
of having all the outside users of PathRegistry worry about it,
to produce a path that is much more consistent. Paths are now
consistent with mappings in all cases. Special logic to get at
"with_polymorphic" structures and such added also.
- AliasedClass now has two modes, "use_mapper_path" and regular;
"use_mapper_path" is for all those situations where we put an AliasedClass
in for a plain class internally, and want it to "path" with the
plain mapper.
- The AliasedInsp is now the first class "entity" for an AliasedClass,
and is passed around internally and used as attr._parententity
and such. it is the AliasedClass analogue for Mapper.
subclasses are being loaded using with_polymorphic(),
each subclass contains a relationship attribute of the same
name, and eager loading is being applied to one or both.
This is an ongoing bug which can't be immediately fixed,
so since the results are usually wrong in any case it raises an
exception for now. 0.7 has the same issue, so an exception
raise here probably means the code was returning the wrong
data in 0.7. [ticket:2614]
become an externally usable package but still remains within the main sqlalchemy parent package.
in this system, we use kind of an ugly hack to get the noseplugin imported outside of the
"sqlalchemy" package, while still making it available within sqlalchemy for usage by
third party libraries.
loading dealing with chains of subclass entities
sharing a common base, with no specific "join depth"
provided. Will chain out to
each subclass mapper individually before detecting
a "cycle", rather than considering the base class
to be the source of the "cycle". [ticket:2481]
now accepts aliased() class constructs as well
as with_polymorphic constructs, and works with
query.join(), any(), has(), and also
eager loaders subqueryload(), joinedload(),
contains_eager()
[ticket:2438] [ticket:1106]
- a rewrite of the query path system to use an
object based approach for more succinct usage. the system
has been designed carefully to not add an excessive method overhead.
- [feature] select() features a correlate_except()
method, auto correlates all selectables except those
passed. Is needed here for the updated any()/has()
functionality.
- remove some old cruft from LoaderStrategy, init(),debug_callable()
- use a namedtuple for _extended_entity_info. This method should
become standard within the orm internals
- some tweaks to the memory profile tests, number of runs can
be customized to work around pysqlite's very annoying behavior
- try to simplify PropertyOption._get_paths(), rename to _process_paths(),
returns a single list now. overall works more completely as was needed
for of_type() functionality
a polymorphic mapping to a target would incur
a new invocation of the query for each
distinct class encountered in the polymorphic
result. [ticket:2480]. Also in 0.7.8.
loading will now traverse already-present related
objects and collections in search of unpopulated
attributes throughout the scope of the eager load
being defined, so that the eager loading that is
specified via mappings or query options
unconditionally takes place for the full depth,
populating whatever is not already populated.
Previously, this traversal would stop if a related
object or collection were already present leading
to inconsistent behavior (though would save on
loads/cycles for an already-loaded graph). For a
subqueryload, this means that the additional
SELECT statements emitted by subqueryload will
invoke unconditionally, no matter how much of the
existing graph is already present (hence the
controversy). The previous behavior of "stopping"
is still in effect when a query is the result of
an attribute-initiated lazyload, as otherwise an
"N+1" style of collection iteration can become
needlessly expensive when the same related object
is encountered repeatedly. There's also an
as-yet-not-public generative Query method
_with_invoke_all_eagers()
which selects old/new behavior [ticket:2213]
access to the cls/self.tables/classes registries
- express orm/_base.py ORMTest in terms of engine/_base.py TablesTest,
factor out common steps into TablesTest, remove AltEngineTest as a
separate class. will further consolidate these base classes
population - added an assertion for when
set_committed_value() is called, as well as
when joinedload() or subqueryload() options
are applied to a dynamic attribute, instead
of failure / silent failure. [ticket:1864]
the values of bind parameters, i.e. those specified
by query.params(), into the resulting SQL expression.
Previously the values would not be transferred
and bind parameters would come out as None.
- Subquery-eager-loading now works with Query objects
which include params(), as well as get() Queries.
loading available, the new names for eagerload() and
eagerload_all() are joinedload() and joinedload_all(). The
old names will remain as synonyms for the foreseeable future.
- The "lazy" flag on the relationship() function now accepts
a string argument for all kinds of loading: "select", "joined",
"subquery", "noload" and "dynamic", where the default is now
"select". The old values of True/
False/None still retain their usual meanings and will remain
as synonyms for the foreseeable future.
- Added documentation to tutorial,mapper doc, api docs
for subqueryload, subqueryload_all, and other options.
such that "remote" eager loads, i.e. eagerloads off of a lazy
load such as query(A).options(eagerload(A.b, B.c))
wouldn't eagerload anything, but using eagerload("b.c") would
work fine.
- subquery eagerloading very close
Mike Bayer