Key ORM constructs, not otherwise covered in other sections, are listed here.
sqlalchemy.orm.state.
AttributeState
(state, key)¶Provide an inspection interface corresponding to a particular attribute on a particular mapped object.
The AttributeState
object is accessed
via the InstanceState.attrs
collection
of a particular InstanceState
:
from sqlalchemy import inspect
insp = inspect(some_mapped_object)
attr_state = insp.attrs.some_attribute
history
¶Return the current pre-flush change history for
this attribute, via the History
interface.
This method will not emit loader callables if the value of the attribute is unloaded.
See also
AttributeState.load_history()
- retrieve history
using loader callables if the value is not locally present.
attributes.get_history()
- underlying function
load_history
()¶Return the current pre-flush change history for
this attribute, via the History
interface.
This method will emit loader callables if the value of the attribute is unloaded.
New in version 0.9.0.
loaded_value
¶The current value of this attribute as loaded from the database.
If the value has not been loaded, or is otherwise not present in the object’s dictionary, returns NO_VALUE.
value
¶Return the value of this attribute.
This operation is equivalent to accessing the object’s
attribute directly or via getattr()
, and will fire
off any pending loader callables if needed.
sqlalchemy.orm.util.
CascadeOptions
¶Bases: __builtin__.frozenset
Keeps track of the options sent to relationship().cascade
sqlalchemy.orm.instrumentation.
ClassManager
(class_)¶Bases: __builtin__.dict
tracks state information at the class level.
__le__
¶__le__
attribute of dict
x.__le__(y) <==> x<=y
__lt__
¶__lt__
attribute of dict
x.__lt__(y) <==> x<y
__ne__
¶__ne__
attribute of dict
x.__ne__(y) <==> x!=y
clear
() → None. Remove all items from D.¶clear()
method of dict
copy
() → a shallow copy of D¶copy()
method of dict
dispose
()¶Dissasociate this manager from its class.
fromkeys
(S[, v]) → New dict with keys from S and values equal to v.¶fromkeys()
method of dict
v defaults to None.
get
(k[, d]) → D[k] if k in D, else d. d defaults to None.¶get()
method of dict
has_key
(k) → True if D has a key k, else False¶has_key()
method of dict
has_parent
(state, key, optimistic=False)¶TODO
items
() → list of D's (key, value) pairs, as 2-tuples¶items()
method of dict
iteritems
() → an iterator over the (key, value) items of D¶iteritems()
method of dict
iterkeys
() → an iterator over the keys of D¶iterkeys()
method of dict
itervalues
() → an iterator over the values of D¶itervalues()
method of dict
keys
() → list of D's keys¶keys()
method of dict
manage
()¶Mark this instance as the manager for its class.
original_init
¶x.__init__(...) initializes x; see help(type(x)) for signature
pop
(k[, d]) → v, remove specified key and return the corresponding value.¶pop()
method of dict
If key is not found, d is returned if given, otherwise KeyError is raised
popitem
() → (k, v), remove and return some (key, value) pair as a¶popitem()
method of dict
2-tuple; but raise KeyError if D is empty.
setdefault
(k[, d]) → D.get(k,d), also set D[k]=d if k not in D¶setdefault()
method of dict
state_getter
()¶Return a (instance) -> InstanceState callable.
“state getter” callables should raise either KeyError or AttributeError if no InstanceState could be found for the instance.
unregister
()¶remove all instrumentation established by this ClassManager.
update
([E, ]**F) → None. Update D from dict/iterable E and F.¶update()
method of dict
If E present and has a .keys() method, does: for k in E: D[k] = E[k] If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k]
values
() → list of D's values¶values()
method of dict
viewitems
() → a set-like object providing a view on D's items¶viewitems()
method of dict
viewkeys
() → a set-like object providing a view on D's keys¶viewkeys()
method of dict
viewvalues
() → an object providing a view on D's values¶viewvalues()
method of dict
sqlalchemy.orm.properties.
ColumnProperty
(*columns, **kwargs)¶Bases: sqlalchemy.orm.interfaces.StrategizedProperty
Describes an object attribute that corresponds to a table column.
Public constructor is the orm.column_property()
function.
Comparator
(prop, parentmapper, adapt_to_entity=None)¶Bases: sqlalchemy.util.langhelpers.MemoizedSlots
, sqlalchemy.orm.interfaces.PropComparator
Produce boolean, comparison, and other operators for
ColumnProperty
attributes.
See the documentation for PropComparator
for a brief
overview.
See also:
Redefining and Creating New Operators
__eq__
(other)¶__eq__()
method of ColumnOperators
Implement the ==
operator.
In a column context, produces the clause a = b
.
If the target is None
, produces a IS NULL
.
__le__
(other)¶__le__()
method of ColumnOperators
Implement the <=
operator.
In a column context, produces the clause a <= b
.
__lt__
(other)¶__lt__()
method of ColumnOperators
Implement the <
operator.
In a column context, produces the clause a < b
.
__ne__
(other)¶__ne__()
method of ColumnOperators
Implement the !=
operator.
In a column context, produces the clause a != b
.
If the target is None
, produces a IS NOT NULL
.
adapt_to_entity
(adapt_to_entity)¶adapt_to_entity()
method of PropComparator
Return a copy of this PropComparator which will use the given
AliasedInsp
to produce corresponding expressions.
adapter
¶adapter
attribute of PropComparator
Produce a callable that adapts column expressions to suit an aliased version of this comparator.
any
(criterion=None, **kwargs)¶any()
method of PropComparator
Return true if this collection contains any member that meets the given criterion.
The usual implementation of any()
is
RelationshipProperty.Comparator.any()
.
Parameters: |
---|
asc
()¶asc()
method of ColumnOperators
Produce a asc()
clause against the
parent object.
between
(cleft, cright, symmetric=False)¶between()
method of ColumnOperators
Produce a between()
clause against
the parent object, given the lower and upper range.
collate
(collation)¶collate()
method of ColumnOperators
Produce a collate()
clause against
the parent object, given the collation string.
concat
(other)¶concat()
method of ColumnOperators
Implement the ‘concat’ operator.
In a column context, produces the clause a || b
,
or uses the concat()
operator on MySQL.
contains
(other, **kwargs)¶contains()
method of ColumnOperators
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
desc
()¶desc()
method of ColumnOperators
Produce a desc()
clause against the
parent object.
distinct
()¶distinct()
method of ColumnOperators
Produce a distinct()
clause against the
parent object.
endswith
(other, **kwargs)¶endswith()
method of ColumnOperators
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
has
(criterion=None, **kwargs)¶has()
method of PropComparator
Return true if this element references a member which meets the given criterion.
The usual implementation of has()
is
RelationshipProperty.Comparator.has()
.
Parameters: |
---|
ilike
(other, escape=None)¶ilike()
method of ColumnOperators
Implement the ilike
operator.
In a column context, produces the clause a ILIKE other
.
E.g.:
select([sometable]).where(sometable.c.column.ilike("%foobar%"))
Parameters: |
---|
See also
in_
(other)¶in_()
method of ColumnOperators
Implement the in
operator.
In a column context, produces the clause a IN other
.
“other” may be a tuple/list of column expressions,
or a select()
construct.
is_
(other)¶is_()
method of ColumnOperators
Implement the IS
operator.
Normally, IS
is generated automatically when comparing to a
value of None
, which resolves to NULL
. However, explicit
usage of IS
may be desirable if comparing to boolean values
on certain platforms.
New in version 0.7.9.
See also
isnot
(other)¶isnot()
method of ColumnOperators
Implement the IS NOT
operator.
Normally, IS NOT
is generated automatically when comparing to a
value of None
, which resolves to NULL
. However, explicit
usage of IS NOT
may be desirable if comparing to boolean values
on certain platforms.
New in version 0.7.9.
See also
like
(other, escape=None)¶like()
method of ColumnOperators
Implement the like
operator.
In a column context, produces the clause a LIKE other
.
E.g.:
select([sometable]).where(sometable.c.column.like("%foobar%"))
Parameters: |
---|
See also
match
(other, **kwargs)¶match()
method of ColumnOperators
Implements a database-specific ‘match’ operator.
match()
attempts to resolve to
a MATCH-like function or operator provided by the backend.
Examples include:
x @@ to_tsquery(y)
MATCH (x) AGAINST (y IN BOOLEAN MODE)
CONTAINS(x, y)
notilike
(other, escape=None)¶notilike()
method of ColumnOperators
implement the NOT ILIKE
operator.
This is equivalent to using negation with
ColumnOperators.ilike()
, i.e. ~x.ilike(y)
.
New in version 0.8.
See also
notin_
(other)¶notin_()
method of ColumnOperators
implement the NOT IN
operator.
This is equivalent to using negation with
ColumnOperators.in_()
, i.e. ~x.in_(y)
.
New in version 0.8.
See also
notlike
(other, escape=None)¶notlike()
method of ColumnOperators
implement the NOT LIKE
operator.
This is equivalent to using negation with
ColumnOperators.like()
, i.e. ~x.like(y)
.
New in version 0.8.
See also
nullsfirst
()¶nullsfirst()
method of ColumnOperators
Produce a nullsfirst()
clause against the
parent object.
nullslast
()¶nullslast()
method of ColumnOperators
Produce a nullslast()
clause against the
parent object.
of_type
(class_)¶of_type()
method of PropComparator
Redefine this object in terms of a polymorphic subclass.
Returns a new PropComparator from which further criterion can be evaluated.
e.g.:
query.join(Company.employees.of_type(Engineer)).\
filter(Engineer.name=='foo')
Parameters: | class_¶ – a class or mapper indicating that criterion will be against this specific subclass. |
---|
op
(opstring, precedence=0, is_comparison=False)¶produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn
.
Parameters: |
|
---|
startswith
(other, **kwargs)¶startswith()
method of ColumnOperators
Implement the startwith
operator.
In a column context, produces the clause LIKE '<other>%'
ColumnProperty.
__init__
(*columns, **kwargs)¶Construct a new ColumnProperty
object.
This constructor is mirrored as a public API function; see column_property()
for a full usage and argument description.
ColumnProperty.
cascade_iterator
(type_, state, visited_instances=None, halt_on=None)¶cascade_iterator()
method of MapperProperty
Iterate through instances related to the given instance for a particular ‘cascade’, starting with this MapperProperty.
Return an iterator3-tuples (instance, mapper, state).
Note that the ‘cascade’ collection on this MapperProperty is checked first for the given type before cascade_iterator is called.
This method typically only applies to RelationshipProperty.
ColumnProperty.
class_attribute
¶class_attribute
attribute of MapperProperty
Return the class-bound descriptor corresponding to this
MapperProperty
.
This is basically a getattr()
call:
return getattr(self.parent.class_, self.key)
I.e. if this MapperProperty
were named addresses
,
and the class to which it is mapped is User
, this sequence
is possible:
>>> from sqlalchemy import inspect
>>> mapper = inspect(User)
>>> addresses_property = mapper.attrs.addresses
>>> addresses_property.class_attribute is User.addresses
True
>>> User.addresses.property is addresses_property
True
ColumnProperty.
expression
¶Return the primary column or expression for this ColumnProperty.
ColumnProperty.
extension_type
= symbol('NOT_EXTENSION')¶ColumnProperty.
init
()¶init()
method of MapperProperty
Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.
ColumnProperty.
set_parent
(parent, init)¶set_parent()
method of MapperProperty
Set the parent mapper that references this MapperProperty.
This method is overridden by some subclasses to perform extra setup when the mapper is first known.
sqlalchemy.orm.properties.
ComparableProperty
(comparator_factory, descriptor=None, doc=None, info=None)¶Bases: sqlalchemy.orm.descriptor_props.DescriptorProperty
Instruments a Python property for use in query expressions.
__init__
(comparator_factory, descriptor=None, doc=None, info=None)¶Construct a new ComparableProperty
object.
This constructor is mirrored as a public API function; see comparable_property()
for a full usage and argument description.
sqlalchemy.orm.descriptor_props.
CompositeProperty
(class_, *attrs, **kwargs)¶Bases: sqlalchemy.orm.descriptor_props.DescriptorProperty
Defines a “composite” mapped attribute, representing a collection of columns as one attribute.
CompositeProperty
is constructed using the composite()
function.
See also
Comparator
(prop, parentmapper, adapt_to_entity=None)¶Bases: sqlalchemy.orm.interfaces.PropComparator
Produce boolean, comparison, and other operators for
CompositeProperty
attributes.
See the example in Redefining Comparison Operations for Composites for an overview
of usage , as well as the documentation for PropComparator
.
See also:
CompositeProperty.
__init__
(class_, *attrs, **kwargs)¶Construct a new CompositeProperty
object.
This constructor is mirrored as a public API function; see composite()
for a full usage and argument description.
CompositeProperty.
do_init
()¶Initialization which occurs after the CompositeProperty
has been associated with its parent mapper.
CompositeProperty.
get_history
(state, dict_, passive=symbol('PASSIVE_OFF'))¶Provided for userland code that uses attributes.get_history().
sqlalchemy.orm.attributes.
Event
(attribute_impl, op)¶A token propagated throughout the course of a chain of attribute events.
Serves as an indicator of the source of the event and also provides a means of controlling propagation across a chain of attribute operations.
The Event
object is sent as the initiator
argument
when dealing with the AttributeEvents.append()
,
AttributeEvents.set()
,
and AttributeEvents.remove()
events.
The Event
object is currently interpreted by the backref
event handlers, and is used to control the propagation of operations
across two mutually-dependent attributes.
New in version 0.9.0.
Variables: |
---|
sqlalchemy.orm.identity.
IdentityMap
¶check_modified
()¶return True if any InstanceStates present have been marked as ‘modified’.
sqlalchemy.orm.base.
InspectionAttr
¶A base class applied to all ORM objects that can be returned
by the inspect()
function.
The attributes defined here allow the usage of simple boolean checks to test basic facts about the object returned.
While the boolean checks here are basically the same as using the Python isinstance() function, the flags here can be used without the need to import all of these classes, and also such that the SQLAlchemy class system can change while leaving the flags here intact for forwards-compatibility.
extension_type
= symbol('NOT_EXTENSION')¶The extension type, if any.
Defaults to interfaces.NOT_EXTENSION
New in version 0.8.0.
is_aliased_class
= False¶True if this object is an instance of AliasedClass
.
is_attribute
= False¶True if this object is a Python descriptor.
This can refer to one of many types. Usually a
QueryableAttribute
which handles attributes events on behalf
of a MapperProperty
. But can also be an extension type
such as AssociationProxy
or hybrid_property
.
The InspectionAttr.extension_type
will refer to a constant
identifying the specific subtype.
See also
is_clause_element
= False¶True if this object is an instance of ClauseElement
.
is_instance
= False¶True if this object is an instance of InstanceState
.
is_property
= False¶True if this object is an instance of MapperProperty
.
is_selectable
= False¶Return True if this object is an instance of Selectable
.
sqlalchemy.orm.base.
InspectionAttrInfo
¶Bases: sqlalchemy.orm.base.InspectionAttr
Adds the .info
attribute to InspectionAttr
.
The rationale for InspectionAttr
vs. InspectionAttrInfo
is that the former is compatible as a mixin for classes that specify
__slots__
; this is essentially an implementation artifact.
info
¶Info dictionary associated with the object, allowing user-defined
data to be associated with this InspectionAttr
.
The dictionary is generated when first accessed. Alternatively,
it can be specified as a constructor argument to the
column_property()
, relationship()
, or composite()
functions.
New in version 0.8: Added support for .info to all
MapperProperty
subclasses.
Changed in version 1.0.0: MapperProperty.info
is also
available on extension types via the
InspectionAttrInfo.info
attribute, so that it can apply
to a wider variety of ORM and extension constructs.
sqlalchemy.orm.state.
InstanceState
(obj, manager)¶Bases: sqlalchemy.orm.base.InspectionAttr
tracks state information at the instance level.
The InstanceState
is a key object used by the
SQLAlchemy ORM in order to track the state of an object;
it is created the moment an object is instantiated, typically
as a result of instrumentation which SQLAlchemy applies
to the __init__()
method of the class.
InstanceState
is also a semi-public object,
available for runtime inspection as to the state of a
mapped instance, including information such as its current
status within a particular Session
and details
about data on individual attributes. The public API
in order to acquire a InstanceState
object
is to use the inspect()
system:
>>> from sqlalchemy import inspect
>>> insp = inspect(some_mapped_object)
See also
attrs
¶Return a namespace representing each attribute on the mapped object, including its current value and history.
The returned object is an instance of AttributeState
.
This object allows inspection of the current data
within an attribute as well as attribute history
since the last flush.
callables
= ()¶A namespace where a per-state loader callable can be associated.
In SQLAlchemy 1.0, this is only used for lazy loaders / deferred loaders that were set up via query option.
Previously, callables was used also to indicate expired attributes by storing a link to the InstanceState itself in this dictionary. This role is now handled by the expired_attributes set.
dict
¶Return the instance dict used by the object.
Under normal circumstances, this is always synonymous
with the __dict__
attribute of the mapped object,
unless an alternative instrumentation system has been
configured.
In the case that the actual object has been garbage collected, this accessor returns a blank dictionary.
expired_attributes
= None¶The set of keys which are ‘expired’ to be loaded by the manager’s deferred scalar loader, assuming no pending changes.
see also the unmodified
collection which is intersected
against this set when a refresh operation occurs.
has_identity
¶Return True
if this object has an identity key.
This should always have the same value as the
expression state.persistent or state.detached
.
identity
¶Return the mapped identity of the mapped object.
This is the primary key identity as persisted by the ORM
which can always be passed directly to
Query.get()
.
Returns None
if the object has no primary key identity.
Note
An object which is transient or pending does not have a mapped identity until it is flushed, even if its attributes include primary key values.
identity_key
¶Return the identity key for the mapped object.
This is the key used to locate the object within
the Session.identity_map
mapping. It contains
the identity as returned by identity
within it.
object
¶Return the mapped object represented by this
InstanceState
.
persistent
¶Return true if the object is persistent.
See also
session
¶Return the owning Session
for this instance,
or None
if none available.
Note that the result here can in some cases be different
from that of obj in session
; an object that’s been deleted
will report as not in session
, however if the transaction is
still in progress, this attribute will still refer to that session.
Only when the transaction is completed does the object become
fully detached under normal circumstances.
unloaded
¶Return the set of keys which do not have a loaded value.
This includes expired attributes and any other attribute that was never populated or modified.
unmodified
¶Return the set of keys which have no uncommitted changes
unmodified_intersection
(keys)¶Return self.unmodified.intersection(keys).
sqlalchemy.orm.attributes.
InstrumentedAttribute
(class_, key, impl=None, comparator=None, parententity=None, of_type=None)¶Bases: sqlalchemy.orm.attributes.QueryableAttribute
Class bound instrumented attribute which adds basic descriptor methods.
See QueryableAttribute
for a description of most features.
__delete__
(instance)¶__get__
(instance, owner)¶__set__
(instance, value)¶sqlalchemy.orm.interfaces.
MANYTOONE
= symbol('MANYTOONE')¶Indicates the many-to-one direction for a relationship()
.
This symbol is typically used by the internals but may be exposed within certain API features.
sqlalchemy.orm.interfaces.
MANYTOMANY
= symbol('MANYTOMANY')¶Indicates the many-to-many direction for a relationship()
.
This symbol is typically used by the internals but may be exposed within certain API features.
sqlalchemy.orm.interfaces.
MapperProperty
¶Bases: sqlalchemy.orm.base._MappedAttribute
, sqlalchemy.orm.base.InspectionAttr
, sqlalchemy.util.langhelpers.MemoizedSlots
Represent a particular class attribute mapped by Mapper
.
The most common occurrences of MapperProperty
are the
mapped Column
, which is represented in a mapping as
an instance of ColumnProperty
,
and a reference to another class produced by relationship()
,
represented in the mapping as an instance of
RelationshipProperty
.
info
¶Info dictionary associated with the object, allowing user-defined
data to be associated with this InspectionAttr
.
The dictionary is generated when first accessed. Alternatively,
it can be specified as a constructor argument to the
column_property()
, relationship()
, or composite()
functions.
New in version 0.8: Added support for .info to all
MapperProperty
subclasses.
Changed in version 1.0.0: InspectionAttr.info
moved
from MapperProperty
so that it can apply to a wider
variety of ORM and extension constructs.
cascade
= frozenset([])¶The set of ‘cascade’ attribute names.
This collection is checked before the ‘cascade_iterator’ method is called.
The collection typically only applies to a RelationshipProperty.
cascade_iterator
(type_, state, visited_instances=None, halt_on=None)¶Iterate through instances related to the given instance for a particular ‘cascade’, starting with this MapperProperty.
Return an iterator3-tuples (instance, mapper, state).
Note that the ‘cascade’ collection on this MapperProperty is checked first for the given type before cascade_iterator is called.
This method typically only applies to RelationshipProperty.
class_attribute
¶Return the class-bound descriptor corresponding to this
MapperProperty
.
This is basically a getattr()
call:
return getattr(self.parent.class_, self.key)
I.e. if this MapperProperty
were named addresses
,
and the class to which it is mapped is User
, this sequence
is possible:
>>> from sqlalchemy import inspect
>>> mapper = inspect(User)
>>> addresses_property = mapper.attrs.addresses
>>> addresses_property.class_attribute is User.addresses
True
>>> User.addresses.property is addresses_property
True
create_row_processor
(context, path, mapper, result, adapter, populators)¶Produce row processing functions and append to the given set of populators lists.
do_init
()¶Perform subclass-specific initialization post-mapper-creation steps.
This is a template method called by the MapperProperty
object’s init() method.
init
()¶Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.
instrument_class
(mapper)¶Hook called by the Mapper to the property to initiate instrumentation of the class attribute managed by this MapperProperty.
The MapperProperty here will typically call out to the attributes module to set up an InstrumentedAttribute.
This step is the first of two steps to set up an InstrumentedAttribute, and is called early in the mapper setup process.
The second step is typically the init_class_attribute step, called from StrategizedProperty via the post_instrument_class() hook. This step assigns additional state to the InstrumentedAttribute (specifically the “impl”) which has been determined after the MapperProperty has determined what kind of persistence management it needs to do (e.g. scalar, object, collection, etc).
is_property
= True¶Part of the InspectionAttr interface; states this object is a mapper property.
merge
(session, source_state, source_dict, dest_state, dest_dict, load, _recursive)¶Merge the attribute represented by this MapperProperty
from source to destination object.
post_instrument_class
(mapper)¶Perform instrumentation adjustments that need to occur after init() has completed.
The given Mapper is the Mapper invoking the operation, which may not be the same Mapper as self.parent in an inheritance scenario; however, Mapper will always at least be a sub-mapper of self.parent.
This method is typically used by StrategizedProperty, which delegates it to LoaderStrategy.init_class_attribute() to perform final setup on the class-bound InstrumentedAttribute.
set_parent
(parent, init)¶Set the parent mapper that references this MapperProperty.
This method is overridden by some subclasses to perform extra setup when the mapper is first known.
setup
(context, entity, path, adapter, **kwargs)¶Called by Query for the purposes of constructing a SQL statement.
Each MapperProperty associated with the target mapper processes the statement referenced by the query context, adding columns and/or criterion as appropriate.
sqlalchemy.orm.interfaces.
NOT_EXTENSION
= symbol('NOT_EXTENSION')¶Symbol indicating an InspectionAttr
that’s
not part of sqlalchemy.ext.
Is assigned to the InspectionAttr.extension_type
attibute.
sqlalchemy.orm.interfaces.
ONETOMANY
= symbol('ONETOMANY')¶Indicates the one-to-many direction for a relationship()
.
This symbol is typically used by the internals but may be exposed within certain API features.
sqlalchemy.orm.interfaces.
PropComparator
(prop, parentmapper, adapt_to_entity=None)¶Bases: sqlalchemy.sql.operators.ColumnOperators
Defines SQL operators for MapperProperty
objects.
SQLAlchemy allows for operators to
be redefined at both the Core and ORM level. PropComparator
is the base class of operator redefinition for ORM-level operations,
including those of ColumnProperty
,
RelationshipProperty
, and CompositeProperty
.
Note
With the advent of Hybrid properties introduced in SQLAlchemy
0.7, as well as Core-level operator redefinition in
SQLAlchemy 0.8, the use case for user-defined PropComparator
instances is extremely rare. See Hybrid Attributes as well
as Redefining and Creating New Operators.
User-defined subclasses of PropComparator
may be created. The
built-in Python comparison and math operator methods, such as
operators.ColumnOperators.__eq__()
,
operators.ColumnOperators.__lt__()
, and
operators.ColumnOperators.__add__()
, can be overridden to provide
new operator behavior. The custom PropComparator
is passed to
the MapperProperty
instance via the comparator_factory
argument. In each case,
the appropriate subclass of PropComparator
should be used:
# definition of custom PropComparator subclasses
from sqlalchemy.orm.properties import \
ColumnProperty,\
CompositeProperty,\
RelationshipProperty
class MyColumnComparator(ColumnProperty.Comparator):
def __eq__(self, other):
return self.__clause_element__() == other
class MyRelationshipComparator(RelationshipProperty.Comparator):
def any(self, expression):
"define the 'any' operation"
# ...
class MyCompositeComparator(CompositeProperty.Comparator):
def __gt__(self, other):
"redefine the 'greater than' operation"
return sql.and_(*[a>b for a, b in
zip(self.__clause_element__().clauses,
other.__composite_values__())])
# application of custom PropComparator subclasses
from sqlalchemy.orm import column_property, relationship, composite
from sqlalchemy import Column, String
class SomeMappedClass(Base):
some_column = column_property(Column("some_column", String),
comparator_factory=MyColumnComparator)
some_relationship = relationship(SomeOtherClass,
comparator_factory=MyRelationshipComparator)
some_composite = composite(
Column("a", String), Column("b", String),
comparator_factory=MyCompositeComparator
)
Note that for column-level operator redefinition, it’s usually
simpler to define the operators at the Core level, using the
TypeEngine.comparator_factory
attribute. See
Redefining and Creating New Operators for more detail.
See also:
RelationshipProperty.Comparator
Redefining and Creating New Operators
__eq__
(other)¶__eq__()
method of ColumnOperators
Implement the ==
operator.
In a column context, produces the clause a = b
.
If the target is None
, produces a IS NULL
.
__le__
(other)¶__le__()
method of ColumnOperators
Implement the <=
operator.
In a column context, produces the clause a <= b
.
__lt__
(other)¶__lt__()
method of ColumnOperators
Implement the <
operator.
In a column context, produces the clause a < b
.
__ne__
(other)¶__ne__()
method of ColumnOperators
Implement the !=
operator.
In a column context, produces the clause a != b
.
If the target is None
, produces a IS NOT NULL
.
adapt_to_entity
(adapt_to_entity)¶Return a copy of this PropComparator which will use the given
AliasedInsp
to produce corresponding expressions.
adapter
¶Produce a callable that adapts column expressions to suit an aliased version of this comparator.
any
(criterion=None, **kwargs)¶Return true if this collection contains any member that meets the given criterion.
The usual implementation of any()
is
RelationshipProperty.Comparator.any()
.
Parameters: |
---|
asc
()¶asc()
method of ColumnOperators
Produce a asc()
clause against the
parent object.
between
(cleft, cright, symmetric=False)¶between()
method of ColumnOperators
Produce a between()
clause against
the parent object, given the lower and upper range.
collate
(collation)¶collate()
method of ColumnOperators
Produce a collate()
clause against
the parent object, given the collation string.
concat
(other)¶concat()
method of ColumnOperators
Implement the ‘concat’ operator.
In a column context, produces the clause a || b
,
or uses the concat()
operator on MySQL.
contains
(other, **kwargs)¶contains()
method of ColumnOperators
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
desc
()¶desc()
method of ColumnOperators
Produce a desc()
clause against the
parent object.
distinct
()¶distinct()
method of ColumnOperators
Produce a distinct()
clause against the
parent object.
endswith
(other, **kwargs)¶endswith()
method of ColumnOperators
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
has
(criterion=None, **kwargs)¶Return true if this element references a member which meets the given criterion.
The usual implementation of has()
is
RelationshipProperty.Comparator.has()
.
Parameters: |
---|
ilike
(other, escape=None)¶ilike()
method of ColumnOperators
Implement the ilike
operator.
In a column context, produces the clause a ILIKE other
.
E.g.:
select([sometable]).where(sometable.c.column.ilike("%foobar%"))
Parameters: |
---|
See also
in_
(other)¶in_()
method of ColumnOperators
Implement the in
operator.
In a column context, produces the clause a IN other
.
“other” may be a tuple/list of column expressions,
or a select()
construct.
is_
(other)¶is_()
method of ColumnOperators
Implement the IS
operator.
Normally, IS
is generated automatically when comparing to a
value of None
, which resolves to NULL
. However, explicit
usage of IS
may be desirable if comparing to boolean values
on certain platforms.
New in version 0.7.9.
See also
isnot
(other)¶isnot()
method of ColumnOperators
Implement the IS NOT
operator.
Normally, IS NOT
is generated automatically when comparing to a
value of None
, which resolves to NULL
. However, explicit
usage of IS NOT
may be desirable if comparing to boolean values
on certain platforms.
New in version 0.7.9.
See also
like
(other, escape=None)¶like()
method of ColumnOperators
Implement the like
operator.
In a column context, produces the clause a LIKE other
.
E.g.:
select([sometable]).where(sometable.c.column.like("%foobar%"))
Parameters: |
---|
See also
match
(other, **kwargs)¶match()
method of ColumnOperators
Implements a database-specific ‘match’ operator.
match()
attempts to resolve to
a MATCH-like function or operator provided by the backend.
Examples include:
x @@ to_tsquery(y)
MATCH (x) AGAINST (y IN BOOLEAN MODE)
CONTAINS(x, y)
notilike
(other, escape=None)¶notilike()
method of ColumnOperators
implement the NOT ILIKE
operator.
This is equivalent to using negation with
ColumnOperators.ilike()
, i.e. ~x.ilike(y)
.
New in version 0.8.
See also
notin_
(other)¶notin_()
method of ColumnOperators
implement the NOT IN
operator.
This is equivalent to using negation with
ColumnOperators.in_()
, i.e. ~x.in_(y)
.
New in version 0.8.
See also
notlike
(other, escape=None)¶notlike()
method of ColumnOperators
implement the NOT LIKE
operator.
This is equivalent to using negation with
ColumnOperators.like()
, i.e. ~x.like(y)
.
New in version 0.8.
See also
nullsfirst
()¶nullsfirst()
method of ColumnOperators
Produce a nullsfirst()
clause against the
parent object.
nullslast
()¶nullslast()
method of ColumnOperators
Produce a nullslast()
clause against the
parent object.
of_type
(class_)¶Redefine this object in terms of a polymorphic subclass.
Returns a new PropComparator from which further criterion can be evaluated.
e.g.:
query.join(Company.employees.of_type(Engineer)).\
filter(Engineer.name=='foo')
Parameters: | class_¶ – a class or mapper indicating that criterion will be against this specific subclass. |
---|
op
(opstring, precedence=0, is_comparison=False)¶produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn
.
Parameters: |
|
---|
operate
(op, *other, **kwargs)¶Operate on an argument.
This is the lowest level of operation, raises
NotImplementedError
by default.
Overriding this on a subclass can allow common
behavior to be applied to all operations.
For example, overriding ColumnOperators
to apply func.lower()
to the left and right
side:
class MyComparator(ColumnOperators):
def operate(self, op, other):
return op(func.lower(self), func.lower(other))
Parameters: |
---|
reverse_operate
(op, other, **kwargs)¶reverse_operate()
method of Operators
Reverse operate on an argument.
Usage is the same as operate()
.
startswith
(other, **kwargs)¶startswith()
method of ColumnOperators
Implement the startwith
operator.
In a column context, produces the clause LIKE '<other>%'
sqlalchemy.orm.properties.
RelationshipProperty
(argument, secondary=None, primaryjoin=None, secondaryjoin=None, foreign_keys=None, uselist=None, order_by=False, backref=None, back_populates=None, post_update=False, cascade=False, extension=None, viewonly=False, lazy=True, collection_class=None, passive_deletes=False, passive_updates=True, remote_side=None, enable_typechecks=True, join_depth=None, comparator_factory=None, single_parent=False, innerjoin=False, distinct_target_key=None, doc=None, active_history=False, cascade_backrefs=True, load_on_pending=False, bake_queries=True, strategy_class=None, _local_remote_pairs=None, query_class=None, info=None)¶Bases: sqlalchemy.orm.interfaces.StrategizedProperty
Describes an object property that holds a single item or list of items that correspond to a related database table.
Public constructor is the orm.relationship()
function.
See also:
Comparator
(prop, parentmapper, adapt_to_entity=None, of_type=None)¶Bases: sqlalchemy.orm.interfaces.PropComparator
Produce boolean, comparison, and other operators for
RelationshipProperty
attributes.
See the documentation for PropComparator
for a brief
overview of ORM level operator definition.
See also:
Redefining and Creating New Operators
__eq__
(other)¶Implement the ==
operator.
In a many-to-one context, such as:
MyClass.some_prop == <some object>
this will typically produce a clause such as:
mytable.related_id == <some id>
Where <some id>
is the primary key of the given
object.
The ==
operator provides partial functionality for non-
many-to-one comparisons:
contains()
.has()
for
more comprehensive non-many-to-one scalar
membership tests.None
given in a one-to-many
or many-to-many context produce a NOT EXISTS clause.__init__
(prop, parentmapper, adapt_to_entity=None, of_type=None)¶Construction of RelationshipProperty.Comparator
is internal to the ORM’s attribute mechanics.
__le__
(other)¶__le__()
method of ColumnOperators
Implement the <=
operator.
In a column context, produces the clause a <= b
.
__lt__
(other)¶__lt__()
method of ColumnOperators
Implement the <
operator.
In a column context, produces the clause a < b
.
__ne__
(other)¶Implement the !=
operator.
In a many-to-one context, such as:
MyClass.some_prop != <some object>
This will typically produce a clause such as:
mytable.related_id != <some id>
Where <some id>
is the primary key of the
given object.
The !=
operator provides partial functionality for non-
many-to-one comparisons:
contains()
in conjunction with not_()
.has()
in
conjunction with not_()
for
more comprehensive non-many-to-one scalar
membership tests.None
given in a one-to-many
or many-to-many context produce an EXISTS clause.adapter
¶adapter
attribute of PropComparator
Produce a callable that adapts column expressions to suit an aliased version of this comparator.
any
(criterion=None, **kwargs)¶Produce an expression that tests a collection against particular criterion, using EXISTS.
An expression like:
session.query(MyClass).filter(
MyClass.somereference.any(SomeRelated.x==2)
)
Will produce a query like:
SELECT * FROM my_table WHERE
EXISTS (SELECT 1 FROM related WHERE related.my_id=my_table.id
AND related.x=2)
Because any()
uses
a correlated subquery, its performance is not nearly as
good when compared against large target tables as that of
using a join.
any()
is particularly
useful for testing for empty collections:
session.query(MyClass).filter(
~MyClass.somereference.any()
)
will produce:
SELECT * FROM my_table WHERE
NOT EXISTS (SELECT 1 FROM related WHERE
related.my_id=my_table.id)
any()
is only
valid for collections, i.e. a relationship()
that has uselist=True
. For scalar references,
use has()
.
asc
()¶asc()
method of ColumnOperators
Produce a asc()
clause against the
parent object.
between
(cleft, cright, symmetric=False)¶between()
method of ColumnOperators
Produce a between()
clause against
the parent object, given the lower and upper range.
collate
(collation)¶collate()
method of ColumnOperators
Produce a collate()
clause against
the parent object, given the collation string.
concat
(other)¶concat()
method of ColumnOperators
Implement the ‘concat’ operator.
In a column context, produces the clause a || b
,
or uses the concat()
operator on MySQL.
contains
(other, **kwargs)¶Return a simple expression that tests a collection for containment of a particular item.
contains()
is
only valid for a collection, i.e. a
relationship()
that implements
one-to-many or many-to-many with uselist=True
.
When used in a simple one-to-many context, an expression like:
MyClass.contains(other)
Produces a clause like:
mytable.id == <some id>
Where <some id>
is the value of the foreign key
attribute on other
which refers to the primary
key of its parent object. From this it follows that
contains()
is
very useful when used with simple one-to-many
operations.
For many-to-many operations, the behavior of
contains()
has more caveats. The association table will be
rendered in the statement, producing an “implicit”
join, that is, includes multiple tables in the FROM
clause which are equated in the WHERE clause:
query(MyClass).filter(MyClass.contains(other))
Produces a query like:
SELECT * FROM my_table, my_association_table AS
my_association_table_1 WHERE
my_table.id = my_association_table_1.parent_id
AND my_association_table_1.child_id = <some id>
Where <some id>
would be the primary key of
other
. From the above, it is clear that
contains()
will not work with many-to-many collections when
used in queries that move beyond simple AND
conjunctions, such as multiple
contains()
expressions joined by OR. In such cases subqueries or
explicit “outer joins” will need to be used instead.
See any()
for
a less-performant alternative using EXISTS, or refer
to Query.outerjoin()
as well as Querying with Joins
for more details on constructing outer joins.
desc
()¶desc()
method of ColumnOperators
Produce a desc()
clause against the
parent object.
distinct
()¶distinct()
method of ColumnOperators
Produce a distinct()
clause against the
parent object.
endswith
(other, **kwargs)¶endswith()
method of ColumnOperators
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
has
(criterion=None, **kwargs)¶Produce an expression that tests a scalar reference against particular criterion, using EXISTS.
An expression like:
session.query(MyClass).filter(
MyClass.somereference.has(SomeRelated.x==2)
)
Will produce a query like:
SELECT * FROM my_table WHERE
EXISTS (SELECT 1 FROM related WHERE
related.id==my_table.related_id AND related.x=2)
Because has()
uses
a correlated subquery, its performance is not nearly as
good when compared against large target tables as that of
using a join.
has()
is only
valid for scalar references, i.e. a relationship()
that has uselist=False
. For collection references,
use any()
.
ilike
(other, escape=None)¶ilike()
method of ColumnOperators
Implement the ilike
operator.
In a column context, produces the clause a ILIKE other
.
E.g.:
select([sometable]).where(sometable.c.column.ilike("%foobar%"))
Parameters: |
---|
See also
in_
(other)¶Produce an IN clause - this is not implemented
for relationship()
-based attributes at this time.
is_
(other)¶is_()
method of ColumnOperators
Implement the IS
operator.
Normally, IS
is generated automatically when comparing to a
value of None
, which resolves to NULL
. However, explicit
usage of IS
may be desirable if comparing to boolean values
on certain platforms.
New in version 0.7.9.
See also
isnot
(other)¶isnot()
method of ColumnOperators
Implement the IS NOT
operator.
Normally, IS NOT
is generated automatically when comparing to a
value of None
, which resolves to NULL
. However, explicit
usage of IS NOT
may be desirable if comparing to boolean values
on certain platforms.
New in version 0.7.9.
See also
like
(other, escape=None)¶like()
method of ColumnOperators
Implement the like
operator.
In a column context, produces the clause a LIKE other
.
E.g.:
select([sometable]).where(sometable.c.column.like("%foobar%"))
Parameters: |
---|
See also
mapper
¶The target Mapper
referred to by this
RelationshipProperty.Comparator
.
This is the “target” or “remote” side of the
relationship()
.
match
(other, **kwargs)¶match()
method of ColumnOperators
Implements a database-specific ‘match’ operator.
match()
attempts to resolve to
a MATCH-like function or operator provided by the backend.
Examples include:
x @@ to_tsquery(y)
MATCH (x) AGAINST (y IN BOOLEAN MODE)
CONTAINS(x, y)
notilike
(other, escape=None)¶notilike()
method of ColumnOperators
implement the NOT ILIKE
operator.
This is equivalent to using negation with
ColumnOperators.ilike()
, i.e. ~x.ilike(y)
.
New in version 0.8.
See also
notin_
(other)¶notin_()
method of ColumnOperators
implement the NOT IN
operator.
This is equivalent to using negation with
ColumnOperators.in_()
, i.e. ~x.in_(y)
.
New in version 0.8.
See also
notlike
(other, escape=None)¶notlike()
method of ColumnOperators
implement the NOT LIKE
operator.
This is equivalent to using negation with
ColumnOperators.like()
, i.e. ~x.like(y)
.
New in version 0.8.
See also
nullsfirst
()¶nullsfirst()
method of ColumnOperators
Produce a nullsfirst()
clause against the
parent object.
nullslast
()¶nullslast()
method of ColumnOperators
Produce a nullslast()
clause against the
parent object.
of_type
(cls)¶Produce a construct that represents a particular ‘subtype’ of attribute for the parent class.
Currently this is usable in conjunction with Query.join()
and Query.outerjoin()
.
op
(opstring, precedence=0, is_comparison=False)¶produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn
.
Parameters: |
|
---|
operate
(op, *other, **kwargs)¶Operate on an argument.
This is the lowest level of operation, raises
NotImplementedError
by default.
Overriding this on a subclass can allow common
behavior to be applied to all operations.
For example, overriding ColumnOperators
to apply func.lower()
to the left and right
side:
class MyComparator(ColumnOperators):
def operate(self, op, other):
return op(func.lower(self), func.lower(other))
Parameters: |
---|
reverse_operate
(op, other, **kwargs)¶reverse_operate()
method of Operators
Reverse operate on an argument.
Usage is the same as operate()
.
startswith
(other, **kwargs)¶startswith()
method of ColumnOperators
Implement the startwith
operator.
In a column context, produces the clause LIKE '<other>%'
RelationshipProperty.
__init__
(argument, secondary=None, primaryjoin=None, secondaryjoin=None, foreign_keys=None, uselist=None, order_by=False, backref=None, back_populates=None, post_update=False, cascade=False, extension=None, viewonly=False, lazy=True, collection_class=None, passive_deletes=False, passive_updates=True, remote_side=None, enable_typechecks=True, join_depth=None, comparator_factory=None, single_parent=False, innerjoin=False, distinct_target_key=None, doc=None, active_history=False, cascade_backrefs=True, load_on_pending=False, bake_queries=True, strategy_class=None, _local_remote_pairs=None, query_class=None, info=None)¶Construct a new RelationshipProperty
object.
This constructor is mirrored as a public API function; see relationship()
for a full usage and argument description.
RelationshipProperty.
cascade
¶Return the current cascade setting for this
RelationshipProperty
.
RelationshipProperty.
class_attribute
¶class_attribute
attribute of MapperProperty
Return the class-bound descriptor corresponding to this
MapperProperty
.
This is basically a getattr()
call:
return getattr(self.parent.class_, self.key)
I.e. if this MapperProperty
were named addresses
,
and the class to which it is mapped is User
, this sequence
is possible:
>>> from sqlalchemy import inspect
>>> mapper = inspect(User)
>>> addresses_property = mapper.attrs.addresses
>>> addresses_property.class_attribute is User.addresses
True
>>> User.addresses.property is addresses_property
True
RelationshipProperty.
extension_type
= symbol('NOT_EXTENSION')¶RelationshipProperty.
init
()¶init()
method of MapperProperty
Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.
RelationshipProperty.
mapper
¶Return the targeted Mapper
for this
RelationshipProperty
.
This is a lazy-initializing static attribute.
RelationshipProperty.
set_parent
(parent, init)¶set_parent()
method of MapperProperty
Set the parent mapper that references this MapperProperty.
This method is overridden by some subclasses to perform extra setup when the mapper is first known.
RelationshipProperty.
table
¶Return the selectable linked to this
RelationshipProperty
object’s target
Mapper
.
Deprecated since version 0.7: Use .target
sqlalchemy.orm.descriptor_props.
SynonymProperty
(name, map_column=None, descriptor=None, comparator_factory=None, doc=None, info=None)¶Bases: sqlalchemy.orm.descriptor_props.DescriptorProperty
__init__
(name, map_column=None, descriptor=None, comparator_factory=None, doc=None, info=None)¶Construct a new SynonymProperty
object.
This constructor is mirrored as a public API function; see synonym()
for a full usage and argument description.
cascade_iterator
(type_, state, visited_instances=None, halt_on=None)¶cascade_iterator()
method of MapperProperty
Iterate through instances related to the given instance for a particular ‘cascade’, starting with this MapperProperty.
Return an iterator3-tuples (instance, mapper, state).
Note that the ‘cascade’ collection on this MapperProperty is checked first for the given type before cascade_iterator is called.
This method typically only applies to RelationshipProperty.
class_attribute
¶class_attribute
attribute of MapperProperty
Return the class-bound descriptor corresponding to this
MapperProperty
.
This is basically a getattr()
call:
return getattr(self.parent.class_, self.key)
I.e. if this MapperProperty
were named addresses
,
and the class to which it is mapped is User
, this sequence
is possible:
>>> from sqlalchemy import inspect
>>> mapper = inspect(User)
>>> addresses_property = mapper.attrs.addresses
>>> addresses_property.class_attribute is User.addresses
True
>>> User.addresses.property is addresses_property
True
create_row_processor
(context, path, mapper, result, adapter, populators)¶create_row_processor()
method of MapperProperty
Produce row processing functions and append to the given set of populators lists.
do_init
()¶do_init()
method of MapperProperty
Perform subclass-specific initialization post-mapper-creation steps.
This is a template method called by the MapperProperty
object’s init() method.
extension_type
= symbol('NOT_EXTENSION')¶init
()¶init()
method of MapperProperty
Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.
merge
(session, source_state, source_dict, dest_state, dest_dict, load, _recursive)¶merge()
method of MapperProperty
Merge the attribute represented by this MapperProperty
from source to destination object.
post_instrument_class
(mapper)¶post_instrument_class()
method of MapperProperty
Perform instrumentation adjustments that need to occur after init() has completed.
The given Mapper is the Mapper invoking the operation, which may not be the same Mapper as self.parent in an inheritance scenario; however, Mapper will always at least be a sub-mapper of self.parent.
This method is typically used by StrategizedProperty, which delegates it to LoaderStrategy.init_class_attribute() to perform final setup on the class-bound InstrumentedAttribute.
setup
(context, entity, path, adapter, **kwargs)¶setup()
method of MapperProperty
Called by Query for the purposes of constructing a SQL statement.
Each MapperProperty associated with the target mapper processes the statement referenced by the query context, adding columns and/or criterion as appropriate.
sqlalchemy.orm.query.
QueryContext
(query)¶sqlalchemy.orm.attributes.
QueryableAttribute
(class_, key, impl=None, comparator=None, parententity=None, of_type=None)¶Bases: sqlalchemy.orm.base._MappedAttribute
, sqlalchemy.orm.base.InspectionAttr
, sqlalchemy.orm.interfaces.PropComparator
Base class for descriptor objects that intercept
attribute events on behalf of a MapperProperty
object. The actual MapperProperty
is accessible
via the QueryableAttribute.property
attribute.
__eq__
(other)¶__eq__()
method of ColumnOperators
Implement the ==
operator.
In a column context, produces the clause a = b
.
If the target is None
, produces a IS NULL
.
__le__
(other)¶__le__()
method of ColumnOperators
Implement the <=
operator.
In a column context, produces the clause a <= b
.
__lt__
(other)¶__lt__()
method of ColumnOperators
Implement the <
operator.
In a column context, produces the clause a < b
.
__ne__
(other)¶__ne__()
method of ColumnOperators
Implement the !=
operator.
In a column context, produces the clause a != b
.
If the target is None
, produces a IS NOT NULL
.
adapter
¶adapter
attribute of PropComparator
Produce a callable that adapts column expressions to suit an aliased version of this comparator.
any
(criterion=None, **kwargs)¶any()
method of PropComparator
Return true if this collection contains any member that meets the given criterion.
The usual implementation of any()
is
RelationshipProperty.Comparator.any()
.
Parameters: |
---|
asc
()¶asc()
method of ColumnOperators
Produce a asc()
clause against the
parent object.
between
(cleft, cright, symmetric=False)¶between()
method of ColumnOperators
Produce a between()
clause against
the parent object, given the lower and upper range.
collate
(collation)¶collate()
method of ColumnOperators
Produce a collate()
clause against
the parent object, given the collation string.
concat
(other)¶concat()
method of ColumnOperators
Implement the ‘concat’ operator.
In a column context, produces the clause a || b
,
or uses the concat()
operator on MySQL.
contains
(other, **kwargs)¶contains()
method of ColumnOperators
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
desc
()¶desc()
method of ColumnOperators
Produce a desc()
clause against the
parent object.
distinct
()¶distinct()
method of ColumnOperators
Produce a distinct()
clause against the
parent object.
endswith
(other, **kwargs)¶endswith()
method of ColumnOperators
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
extension_type
= symbol('NOT_EXTENSION')¶has
(criterion=None, **kwargs)¶has()
method of PropComparator
Return true if this element references a member which meets the given criterion.
The usual implementation of has()
is
RelationshipProperty.Comparator.has()
.
Parameters: |
---|
ilike
(other, escape=None)¶ilike()
method of ColumnOperators
Implement the ilike
operator.
In a column context, produces the clause a ILIKE other
.
E.g.:
select([sometable]).where(sometable.c.column.ilike("%foobar%"))
Parameters: |
---|
See also
in_
(other)¶in_()
method of ColumnOperators
Implement the in
operator.
In a column context, produces the clause a IN other
.
“other” may be a tuple/list of column expressions,
or a select()
construct.
info
¶Return the ‘info’ dictionary for the underlying SQL element.
The behavior here is as follows:
ColumnProperty
, which is mapped directly
to a schema-level Column
object, this attribute
will return the SchemaItem.info
dictionary associated
with the core-level Column
object.ColumnProperty
but is mapped to
any other kind of SQL expression other than a Column
,
the attribute will refer to the MapperProperty.info
dictionary associated directly with the ColumnProperty
,
assuming the SQL expression itself does not have its own .info
attribute (which should be the case, unless a user-defined SQL
construct has defined one).MapperProperty
, including RelationshipProperty
,
the attribute will refer to the MapperProperty.info
dictionary associated with that MapperProperty
.MapperProperty.info
dictionary of the
MapperProperty
unconditionally, including for a
ColumnProperty
that’s associated directly with a
schema.Column
, the attribute can be referred to using
QueryableAttribute.property
attribute, as
MyClass.someattribute.property.info
.New in version 0.8.0.
is_
(other)¶is_()
method of ColumnOperators
Implement the IS
operator.
Normally, IS
is generated automatically when comparing to a
value of None
, which resolves to NULL
. However, explicit
usage of IS
may be desirable if comparing to boolean values
on certain platforms.
New in version 0.7.9.
See also
isnot
(other)¶isnot()
method of ColumnOperators
Implement the IS NOT
operator.
Normally, IS NOT
is generated automatically when comparing to a
value of None
, which resolves to NULL
. However, explicit
usage of IS NOT
may be desirable if comparing to boolean values
on certain platforms.
New in version 0.7.9.
See also
like
(other, escape=None)¶like()
method of ColumnOperators
Implement the like
operator.
In a column context, produces the clause a LIKE other
.
E.g.:
select([sometable]).where(sometable.c.column.like("%foobar%"))
Parameters: |
---|
See also
match
(other, **kwargs)¶match()
method of ColumnOperators
Implements a database-specific ‘match’ operator.
match()
attempts to resolve to
a MATCH-like function or operator provided by the backend.
Examples include:
x @@ to_tsquery(y)
MATCH (x) AGAINST (y IN BOOLEAN MODE)
CONTAINS(x, y)
notilike
(other, escape=None)¶notilike()
method of ColumnOperators
implement the NOT ILIKE
operator.
This is equivalent to using negation with
ColumnOperators.ilike()
, i.e. ~x.ilike(y)
.
New in version 0.8.
See also
notin_
(other)¶notin_()
method of ColumnOperators
implement the NOT IN
operator.
This is equivalent to using negation with
ColumnOperators.in_()
, i.e. ~x.in_(y)
.
New in version 0.8.
See also
notlike
(other, escape=None)¶notlike()
method of ColumnOperators
implement the NOT LIKE
operator.
This is equivalent to using negation with
ColumnOperators.like()
, i.e. ~x.like(y)
.
New in version 0.8.
See also
nullsfirst
()¶nullsfirst()
method of ColumnOperators
Produce a nullsfirst()
clause against the
parent object.
nullslast
()¶nullslast()
method of ColumnOperators
Produce a nullslast()
clause against the
parent object.
op
(opstring, precedence=0, is_comparison=False)¶produce a generic operator function.
e.g.:
somecolumn.op("*")(5)
produces:
somecolumn * 5
This function can also be used to make bitwise operators explicit. For example:
somecolumn.op('&')(0xff)
is a bitwise AND of the value in somecolumn
.
Parameters: |
|
---|
parent
¶Return an inspection instance representing the parent.
This will be either an instance of Mapper
or AliasedInsp
, depending upon the nature
of the parent entity which this attribute is associated
with.
property
¶Return the MapperProperty
associated with this
QueryableAttribute
.
Return values here will commonly be instances of
ColumnProperty
or RelationshipProperty
.
startswith
(other, **kwargs)¶startswith()
method of ColumnOperators
Implement the startwith
operator.
In a column context, produces the clause LIKE '<other>%'
sqlalchemy.orm.session.
UOWTransaction
(session)¶filter_states_for_dep
(dep, states)¶Filter the given list of InstanceStates to those relevant to the given DependencyProcessor.
finalize_flush_changes
()¶mark processed objects as clean / deleted after a successful flush().
this method is called within the flush() method after the execute() method has succeeded and the transaction has been committed.
get_attribute_history
(state, key, passive=symbol('PASSIVE_NO_INITIALIZE'))¶facade to attributes.get_state_history(), including caching of results.
is_deleted
(state)¶return true if the given state is marked as deleted within this uowtransaction.
remove_state_actions
(state)¶remove pending actions for a state from the uowtransaction.