is a standardized interface which allows the creation of custom
ClauseElement subclasses and compilers. In particular it's
handy as an alternative to text() when you'd like to
build a construct that has database-specific compilations.
See the extension docs for details.
sqlalchemy.orm.attributes. Given an object, attribute name,
and value, will set the value on the object as part of its
"committed" state, i.e. state that is understood to have
been loaded from the database. Helps with the creation of
homegrown collection loaders and such.
- documented public attributes helper functions.
placed on a many-to-many relation. First, the bad news:
the warning will apply to both many-to-many as well as
many-to-one relations. This is necessary since in both
cases, SQLA does not scan the full set of potential parents
when determining "orphan" status - for a persistent object
it only detects an in-python de-association event to establish
the object as an "orphan". Next, the good news: to support
one-to-one via a foreign key or assocation table, or to
support one-to-many via an association table, a new flag
single_parent=True may be set which indicates objects
linked to the relation are only meant to have a single parent.
The relation will raise an error if multiple parent-association
events occur within Python.
- Fixed bug in delete-orphan cascade whereby two one-to-one
relations from two different parent classes to the same target
class would prematurely expunge the instance. This is
an extension of the non-ticketed fix in r4247.
- the order of "sethasparent" flagging in relation to
AttributeExtensions has been refined such that false setparents
are issued before the event, true setparents issued afterwards.
event handlers "know" that a remove event originates
from a non-orphan but need to know if its become an orphan,
and that append events will become non-orphans but need to know
if the event originates from a non-orphan.
table of their own (i.e. use single table inheritance).
The columns will be appended to the base table, but only
mapped by the subclass.
- For both joined and single inheriting subclasses, the subclass
will only map those columns which are already mapped on the
superclass and those explicit on the subclass. Other
columns that are present on the `Table` will be excluded
from the mapping by default, which can be disabled
by passing a blank `exclude_properties` collection to the
`__mapper_args__`. This is so that single-inheriting
classes which define their own columns are the only classes
to map those columns. The effect is actually a more organized
mapping than you'd normally get with explicit `mapper()`
calls unless you set up the `exclude_properties` arguments
explicitly.
- docs/tests
- Added a new `relation()` keyword `back_populates`. This allows configuation of backreferences using explicit relations. [ticket:781] This is required when creating bidirectional relations between a hierarchy of concrete mappers and another class. [ticket:1237]
- Test coverage added for `relation()` objects specified on concrete mappers. [ticket:1237]
- A short documentation example added for bidirectional relations specified on concrete mappers. [ticket:1237]
- Mappers now instrument class attributes upon construction with the final InstrumentedAttribute object which remains persistent. The `_CompileOnAttr`/`__getattribute__()` methodology has been removed. The net effect is that Column-based mapped class attributes can now be used fully at the class level without invoking a mapper compilation operation, greatly simplifying typical usage patterns within declarative. [ticket:1269]
- Index now accepts column-oriented InstrumentedAttributes (i.e. column-based mapped class attributes) as column arguments. [ticket:1214]
- Broke up attributes.register_attribute into two separate functions register_descriptor and register_attribute_impl. The first assembles an InstrumentedAttribute or Proxy descriptor, the second assembles the AttributeImpl inside the InstrumentedAttribute. register_attribute remains for outside compatibility. The argument lists have been simplified.
- Removed class_manager argument from all but MutableScalarAttributeImpl (the branch had removed class_ as well but this has been reverted locally to support the serializer extension).
- Mapper's previous construction of _CompileOnAttr now moves to a new MapperProperty.instrument_class() method which is called on all MapperProperty objects at the moment the mapper receives them. All MapperProperty objects now call attributes.register_descriptor within that method to assemble an InstrumentedAttribute object directly.
- InstrumentedAttribute now receives the "property" attribute from the given PropComparator. The guesswork within the constructor is removed, and allows "property" to serve as a mapper compilation trigger.
- RelationProperty.Comparator now triggers compilation of its parent mapper within a util.memoized_property accessor for the "property" attribute, which is used instead of "prop" (we can probably remove "prop").
- ColumnProperty and similar handle most of their initialization in their __init__ method since they must function fully at the class level before mappers are compiled.
- SynonymProperty and ComparableProperty move their class instrumentation logic to the new instrument_class() method.
- LoaderStrategy objects now add their state to existing InstrumentedAttributes using attributes.register_attribute_impl. Both column and relation-based loaders instrument in the same way now, with a unique InstrumentedAttribute *and* a unique AttributeImpl for each class in the hierarchy. attribute.parententity should now be correct in all cases.
- Removed unitofwork.register_attribute, and simpified the _register_attribute methods into a single function in strategies.py. unitofwork exports the UOWEventHandler extension directly.
- To accomodate the multiple AttributeImpls across a class hierarchy, the sethasparent() method now uses an optional "parent_token" attribute to identify the "parent". AbstractRelationLoader sends the MapperProperty along to serve as this token. If the token isn't present (which is only the case in the attributes unit tests), the AttributeImpl is used instead, which is essentially the same as the old behavior.
- Added new ConcreteInheritedProperty MapperProperty. This is invoked for concrete mappers within _adapt_inherited_property() to accomodate concrete mappers which inherit unhandled attributes from the base class, and basically raises an exception upon access. [ticket:1237]
- attributes.register_attribute and register_descriptor will now re-instrument an attribute unconditionally without checking for a previous attribute. Not sure if this is controversial. It's needed so that ConcreteInheritedProperty instrumentation can be overridden by an incoming legit MapperProperty without any complexity.
- Added new UninstrumentedColumnLoader LoaderStrategy. This is used by the polymorphic_on argument when the given column is not represented within the mapped selectable, as is typical with a concrete scenario which maps to a polymorphic union. It does not configure class instrumentation, keeping polymorphic_on from getting caught up in the new concrete attribute-checking logic.
- RelationProperty now records its "backref" attributes using a set assigned to `_reverse_property` instead of a scalar. The `back_populates` keyword allows any number of properties to be involved in a single bidirectional relation. Changes were needed to RelationProperty.merge(), DependencyProcessor to accomodate for the new multiple nature of this attribute.
- Generalized the methodology used by ManyToManyDP to check for "did the other dependency already handle this direction", building on the `_reverse_property` collection.
- post_update logic within dependency.py moves to use the same methodology as ManyToManyDP so that "did the other dependency do this already" checks are made to be specific to the two dependent instances.
- Caught that RelationProperty.merge() was writing to instance.__dict__ directly (!) - repaired to talk to instance_state.dict.
- Removed needless eager loading example from concrete mapper docs.
- Added test for [ticket:965].
- Added the usual Node class/nodes table to orm/_fixtures.py, but haven't used it for anything yet. We can potentially update test/orm/query.py to use this fixture.
- Other test/documentation cleanup.
their referenced column, even if the column
was given a "key" attribute different from
the reflected name. This is achieved via a
new flag on ForeignKey/ForeignKeyConstraint
called "link_to_name", if True means the given
name is the referred-to column's name, not its
assigned key.
[ticket:650]
- removed column types from sqlite doc, we
aren't going to list out "implementation" types
since they aren't significant and are less present
in 0.6
- mysql will report on missing reflected foreign
key targets in the same way as other dialects
(we can improve that to be immediate within
reflecttable(), but it should be within
ForeignKeyConstraint()).
- postgres dialect can reflect table with
an include_columns list that doesn't include
one or more primary key columns
- Documentation has been converted to Sphinx.
In particular, the generated API documentation
has been constructed into a full blown
"API Reference" section which organizes
editorial documentation combined with
generated docstrings. Cross linking between
sections and API docs are vastly improved,
a javascript-powered search feature is
provided, and a full index of all
classes, functions and members is provided.
- added other unit tests as per [ticket:1149]
- rewrote most of the "joined table inheritance" documentation section, removed badly out of
date "polymorphic_fetch" and "select_table" arguments.
- "select_table" raises a deprecation warning. converted unit tests to not use it.
- removed all references to "ORDER BY table.oid" from mapping docs.
- renamed PropertyLoader to RelationProperty. Old symbol remains.
- renamed ColumnProperty.ColumnComparator to ColumnProperty.Comparator. Old symbol remains.
- Added note about create_session() defaults.
- Added section about metadata.reflect().
- Updated `TypeDecorator` section.
- Rewrote the "threadlocal" strategy section of
the docs due to recent confusion over this
feature.
- ordered the init arguments in the docs for sessionmaker().
- other edits
Mike Bayer