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ORM Internals¶
Key ORM constructs, not otherwise covered in other sections, are listed here.
- class sqlalchemy.orm.state.AttributeState(state, key)¶
Bases: object
Provide an inspection interface corresponding to a particular attribute on a particular mapped object.
The AttributeState object is accessed via the InstanceState.attr collection of a particular InstanceState:
from sqlalchemy import inspect insp = inspect(some_mapped_object) attr_state = insp.attr.some_attribute
- 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.
- class sqlalchemy.orm.instrumentation.ClassManager(class_)¶
Bases: dict
tracks state information at the class level.
- __eq__¶
- inherited from the __eq__ attribute of dict
x.__eq__(y) <==> x==y
- __le__¶
- inherited from the __le__ attribute of dict
x.__le__(y) <==> x<=y
- __lt__¶
- inherited from the __lt__ attribute of dict
x.__lt__(y) <==> x<y
- __ne__¶
- inherited from the __ne__ attribute of dict
x.__ne__(y) <==> x!=y
- clear() → None. Remove all items from D.¶
- inherited from the clear() method of dict
- copy() → a shallow copy of D¶
- inherited from the copy() method of dict
- dispose()¶
Dissasociate this manager from its class.
- static fromkeys(S[, v]) → New dict with keys from S and values equal to v.¶
- inherited from the fromkeys() method of dict
v defaults to None.
- get(k[, d]) → D[k] if k in D, else d. d defaults to None.¶
- inherited from the get() method of dict
- has_key(k) → True if D has a key k, else False¶
- inherited from the has_key() method of dict
- has_parent(state, key, optimistic=False)¶
TODO
- items() → list of D's (key, value) pairs, as 2-tuples¶
- inherited from the items() method of dict
- iteritems() → an iterator over the (key, value) items of D¶
- inherited from the iteritems() method of dict
- iterkeys() → an iterator over the keys of D¶
- inherited from the iterkeys() method of dict
- itervalues() → an iterator over the values of D¶
- inherited from the itervalues() method of dict
- keys() → list of D's keys¶
- inherited from the 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.¶
- inherited from the 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¶
- inherited from the 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¶
- inherited from the setdefault() method of dict
- classmethod 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.¶
- inherited from the 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¶
- inherited from the values() method of dict
- viewitems() → a set-like object providing a view on D's items¶
- inherited from the viewitems() method of dict
- viewkeys() → a set-like object providing a view on D's keys¶
- inherited from the viewkeys() method of dict
- viewvalues() → an object providing a view on D's values¶
- inherited from the viewvalues() method of dict
- class 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.
- ColumnComparator¶
alias of Comparator
- class Comparator(prop, parentmapper, adapter=None)¶
Bases: 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)¶
- inherited from the __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)¶
- inherited from the __le__() method of ColumnOperators
Implement the <= operator.
In a column context, produces the clause a <= b.
- __lt__(other)¶
- inherited from the __lt__() method of ColumnOperators
Implement the < operator.
In a column context, produces the clause a < b.
- __ne__(other)¶
- inherited from the __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.
- adapted(adapter)¶
- inherited from the adapted() method of PropComparator
Return a copy of this PropComparator which will use the given adaption function on the local side of generated expressions.
- any(criterion=None, **kwargs)¶
- inherited from the 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: - criterion – an optional ClauseElement formulated against the member class’ table or attributes.
- **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.
- asc()¶
- inherited from the asc() method of ColumnOperators
Produce a asc() clause against the parent object.
- between(cleft, cright)¶
- inherited from the between() method of ColumnOperators
Produce a between() clause against the parent object, given the lower and upper range.
- collate(collation)¶
- inherited from the collate() method of ColumnOperators
Produce a collate() clause against the parent object, given the collation string.
- concat(other)¶
- inherited from the 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)¶
- inherited from the contains() method of ColumnOperators
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
- desc()¶
- inherited from the desc() method of ColumnOperators
Produce a desc() clause against the parent object.
- distinct()¶
- inherited from the distinct() method of ColumnOperators
Produce a distinct() clause against the parent object.
- endswith(other, **kwargs)¶
- inherited from the endswith() method of ColumnOperators
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
- has(criterion=None, **kwargs)¶
- inherited from the 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: - criterion – an optional ClauseElement formulated against the member class’ table or attributes.
- **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.
- ilike(other, escape=None)¶
- inherited from the 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: - other – expression to be compared
- escape –
optional escape character, renders the ESCAPE keyword, e.g.:
somecolumn.ilike("foo/%bar", escape="/")
See also
- in_(other)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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: - other – expression to be compared
- escape –
optional escape character, renders the ESCAPE keyword, e.g.:
somecolumn.like("foo/%bar", escape="/")
See also
- match(other, **kwargs)¶
- inherited from the match() method of ColumnOperators
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
- notilike(other, escape=None)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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()¶
- inherited from the nullsfirst() method of ColumnOperators
Produce a nullsfirst() clause against the parent object.
- nullslast()¶
- inherited from the nullslast() method of ColumnOperators
Produce a nullslast() clause against the parent object.
- of_type(class_)¶
- inherited from the 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)¶
-
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: - operator – a string which will be output as the infix operator between this element and the expression passed to the generated function.
- precedence –
precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of 0 is lower than all operators except for the comma (,) and AS operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators.
New in version 0.8: - added the ‘precedence’ argument.
- startswith(other, **kwargs)¶
- inherited from the startswith() method of ColumnOperators
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
- ColumnProperty.__init__(*columns, **kwargs)¶
Construct a ColumnProperty.
Note the public constructor is the orm.column_property() function.
Parameters: - *columns – The list of columns describes a single object property. If there are multiple tables joined together for the mapper, this list represents the equivalent column as it appears across each table.
- group –
- deferred –
- comparator_factory –
- descriptor –
- expire_on_flush –
- extension –
- info – Optional data dictionary which will be populated into the info attribute of this object.
- ColumnProperty.cascade_iterator(type_, state, visited_instances=None, halt_on=None)¶
- inherited from the 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.
See PropertyLoader for the related instance implementation.
- ColumnProperty.class_attribute¶
- inherited from the class_attribute attribute of MapperProperty
Return the class-bound descriptor corresponding to this MapperProperty.
- ColumnProperty.compare(operator, value, **kw)¶
- inherited from the compare() method of MapperProperty
Return a compare operation for the columns represented by this MapperProperty to the given value, which may be a column value or an instance. ‘operator’ is an operator from the operators module, or from sql.Comparator.
By default uses the PropComparator attached to this MapperProperty under the attribute name “comparator”.
- ColumnProperty.expression¶
Return the primary column or expression for this ColumnProperty.
- ColumnProperty.info¶
- inherited from the info attribute of MapperProperty
Info dictionary associated with the object, allowing user-defined data to be associated with this MapperProperty.
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.
- ColumnProperty.init()¶
- inherited from the init() method of MapperProperty
Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.
- ColumnProperty.is_primary()¶
- inherited from the is_primary() method of MapperProperty
Return True if this MapperProperty‘s mapper is the primary mapper for its class.
This flag is used to indicate that the MapperProperty can define attribute instrumentation for the class at the class level (as opposed to the individual instance level).
- class 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:
- class Comparator(prop, adapter=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.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().
- class sqlalchemy.orm.interfaces._InspectionAttr¶
Bases: object
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.
- class sqlalchemy.orm.state.InstanceState(obj, manager)¶
Bases: sqlalchemy.orm.interfaces._InspectionAttr
tracks state information at the instance level.
- __call__(passive)¶
__call__ allows the InstanceState to act as a deferred callable for loading expired attributes, which is also serializable (picklable).
- 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.
- detached¶
Return true if the object is detached.
- expired_attributes¶
Return 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.
- pending¶
Return true if the object is pending.
- persistent¶
Return true if the object is persistent.
- transient¶
Return true if the object is transient.
- 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).
- class 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.
- __get__(instance, owner)¶
- __set__(instance, value)¶
- __delete__(instance)¶
- class sqlalchemy.orm.interfaces.MapperProperty¶
Bases: sqlalchemy.orm.interfaces._MappedAttribute, sqlalchemy.orm.interfaces._InspectionAttr
Manage the relationship of a Mapper to a single class attribute, as well as that attribute as it appears on individual instances of the class, including attribute instrumentation, attribute access, loading behavior, and dependency calculations.
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.
- cascade = frozenset([])¶
The set of ‘cascade’ attribute names.
This collection is checked before the ‘cascade_iterator’ method is called.
- 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.
See PropertyLoader for the related instance implementation.
- class_attribute¶
Return the class-bound descriptor corresponding to this MapperProperty.
- compare(operator, value, **kw)¶
Return a compare operation for the columns represented by this MapperProperty to the given value, which may be a column value or an instance. ‘operator’ is an operator from the operators module, or from sql.Comparator.
By default uses the PropComparator attached to this MapperProperty under the attribute name “comparator”.
- create_row_processor(context, path, mapper, row, adapter)¶
Return a 3-tuple consisting of three row processing functions.
- do_init()¶
Perform subclass-specific initialization post-mapper-creation steps.
This is a template method called by the MapperProperty object’s init() method.
- info¶
Info dictionary associated with the object, allowing user-defined data to be associated with this MapperProperty.
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.
- init()¶
Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.
- is_primary()¶
Return True if this MapperProperty‘s mapper is the primary mapper for its class.
This flag is used to indicate that the MapperProperty can define attribute instrumentation for the class at the class level (as opposed to the individual instance level).
- 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.
- 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>¶
- class sqlalchemy.orm.interfaces.PropComparator(prop, parentmapper, adapter=None)¶
Bases: sqlalchemy.sql.operators.ColumnOperators
Defines boolean, comparison, and other 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)¶
- inherited from the __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)¶
- inherited from the __le__() method of ColumnOperators
Implement the <= operator.
In a column context, produces the clause a <= b.
- __lt__(other)¶
- inherited from the __lt__() method of ColumnOperators
Implement the < operator.
In a column context, produces the clause a < b.
- __ne__(other)¶
- inherited from the __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.
- adapted(adapter)¶
Return a copy of this PropComparator which will use the given adaption function on the local side of generated expressions.
- 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: - criterion – an optional ClauseElement formulated against the member class’ table or attributes.
- **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.
- asc()¶
- inherited from the asc() method of ColumnOperators
Produce a asc() clause against the parent object.
- between(cleft, cright)¶
- inherited from the between() method of ColumnOperators
Produce a between() clause against the parent object, given the lower and upper range.
- collate(collation)¶
- inherited from the collate() method of ColumnOperators
Produce a collate() clause against the parent object, given the collation string.
- concat(other)¶
- inherited from the 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)¶
- inherited from the contains() method of ColumnOperators
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
- desc()¶
- inherited from the desc() method of ColumnOperators
Produce a desc() clause against the parent object.
- distinct()¶
- inherited from the distinct() method of ColumnOperators
Produce a distinct() clause against the parent object.
- endswith(other, **kwargs)¶
- inherited from the 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: - criterion – an optional ClauseElement formulated against the member class’ table or attributes.
- **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.
- ilike(other, escape=None)¶
- inherited from the 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: - other – expression to be compared
- escape –
optional escape character, renders the ESCAPE keyword, e.g.:
somecolumn.ilike("foo/%bar", escape="/")
See also
- in_(other)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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: - other – expression to be compared
- escape –
optional escape character, renders the ESCAPE keyword, e.g.:
somecolumn.like("foo/%bar", escape="/")
See also
- match(other, **kwargs)¶
- inherited from the match() method of ColumnOperators
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
- notilike(other, escape=None)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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()¶
- inherited from the nullsfirst() method of ColumnOperators
Produce a nullsfirst() clause against the parent object.
- nullslast()¶
- inherited from the 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)¶
-
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: - operator – a string which will be output as the infix operator between this element and the expression passed to the generated function.
- precedence –
precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of 0 is lower than all operators except for the comma (,) and AS operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators.
New in version 0.8: - added the ‘precedence’ argument.
- 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: - op – Operator callable.
- *other – the ‘other’ side of the operation. Will be a single scalar for most operations.
- **kwargs – modifiers. These may be passed by special operators such as ColumnOperators.contains().
- reverse_operate(op, other, **kwargs)¶
- inherited from the reverse_operate() method of Operators
Reverse operate on an argument.
Usage is the same as operate().
- startswith(other, **kwargs)¶
- inherited from the startswith() method of ColumnOperators
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
- class 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, doc=None, active_history=False, cascade_backrefs=True, load_on_pending=False, 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:
- class Comparator(prop, parentmapper, of_type=None, adapter=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:
- Comparisons against collections are not supported. Use contains().
- Compared to a scalar one-to-many, will produce a clause that compares the target columns in the parent to the given target.
- Compared to a scalar many-to-many, an alias of the association table will be rendered as well, forming a natural join that is part of the main body of the query. This will not work for queries that go beyond simple AND conjunctions of comparisons, such as those which use OR. Use explicit joins, outerjoins, or has() for more comprehensive non-many-to-one scalar membership tests.
- Comparisons against None given in a one-to-many or many-to-many context produce a NOT EXISTS clause.
- __init__(prop, parentmapper, of_type=None, adapter=None)¶
Construction of RelationshipProperty.Comparator is internal to the ORM’s attribute mechanics.
- __le__(other)¶
- inherited from the __le__() method of ColumnOperators
Implement the <= operator.
In a column context, produces the clause a <= b.
- __lt__(other)¶
- inherited from the __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:
- Comparisons against collections are not supported. Use contains() in conjunction with not_().
- Compared to a scalar one-to-many, will produce a clause that compares the target columns in the parent to the given target.
- Compared to a scalar many-to-many, an alias of the association table will be rendered as well, forming a natural join that is part of the main body of the query. This will not work for queries that go beyond simple AND conjunctions of comparisons, such as those which use OR. Use explicit joins, outerjoins, or has() in conjunction with not_() for more comprehensive non-many-to-one scalar membership tests.
- Comparisons against None given in a one-to-many or many-to-many context produce an EXISTS clause.
- adapted(adapter)¶
Return a copy of this PropComparator which will use the given adaption function on the local side of generated expressions.
- 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()¶
- inherited from the asc() method of ColumnOperators
Produce a asc() clause against the parent object.
- between(cleft, cright)¶
- inherited from the between() method of ColumnOperators
Produce a between() clause against the parent object, given the lower and upper range.
- collate(collation)¶
- inherited from the collate() method of ColumnOperators
Produce a collate() clause against the parent object, given the collation string.
- concat(other)¶
- inherited from the 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()¶
- inherited from the desc() method of ColumnOperators
Produce a desc() clause against the parent object.
- distinct()¶
- inherited from the distinct() method of ColumnOperators
Produce a distinct() clause against the parent object.
- endswith(other, **kwargs)¶
- inherited from the 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)¶
- inherited from the 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: - other – expression to be compared
- escape –
optional escape character, renders the ESCAPE keyword, e.g.:
somecolumn.ilike("foo/%bar", escape="/")
See also
- in_(other)¶
Produce an IN clause - this is not implemented for relationship()-based attributes at this time.
- is_(other)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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: - other – expression to be compared
- escape –
optional escape character, renders the ESCAPE keyword, e.g.:
somecolumn.like("foo/%bar", escape="/")
See also
- mapper¶
The target Mapper referred to by this :class:`.RelationshipProperty.Comparator.
This is the “target” or “remote” side of the relationship().
- match(other, **kwargs)¶
- inherited from the match() method of ColumnOperators
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
- notilike(other, escape=None)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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()¶
- inherited from the nullsfirst() method of ColumnOperators
Produce a nullsfirst() clause against the parent object.
- nullslast()¶
- inherited from the 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)¶
-
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: - operator – a string which will be output as the infix operator between this element and the expression passed to the generated function.
- precedence –
precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of 0 is lower than all operators except for the comma (,) and AS operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators.
New in version 0.8: - added the ‘precedence’ argument.
- 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: - op – Operator callable.
- *other – the ‘other’ side of the operation. Will be a single scalar for most operations.
- **kwargs – modifiers. These may be passed by special operators such as ColumnOperators.contains().
- reverse_operate(op, other, **kwargs)¶
- inherited from the reverse_operate() method of Operators
Reverse operate on an argument.
Usage is the same as operate().
- startswith(other, **kwargs)¶
- inherited from the startswith() method of ColumnOperators
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
- RelationshipProperty.cascade¶
Return the current cascade setting for this RelationshipProperty.
- RelationshipProperty.class_attribute¶
- inherited from the class_attribute attribute of MapperProperty
Return the class-bound descriptor corresponding to this MapperProperty.
- RelationshipProperty.info¶
- inherited from the info attribute of MapperProperty
Info dictionary associated with the object, allowing user-defined data to be associated with this MapperProperty.
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.
- RelationshipProperty.init()¶
- inherited from the init() method of MapperProperty
Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.
- RelationshipProperty.is_primary()¶
- inherited from the is_primary() method of MapperProperty
Return True if this MapperProperty‘s mapper is the primary mapper for its class.
This flag is used to indicate that the MapperProperty can define attribute instrumentation for the class at the class level (as opposed to the individual instance level).
- RelationshipProperty.mapper¶
Return the targeted Mapper for this RelationshipProperty.
This is a lazy-initializing static attribute.
- RelationshipProperty.table¶
Return the selectable linked to this
Deprecated since version 0.7: Use .target
RelationshipProperty object’s target Mapper.
- class sqlalchemy.orm.descriptor_props.SynonymProperty(name, map_column=None, descriptor=None, comparator_factory=None, doc=None)¶
Bases: sqlalchemy.orm.descriptor_props.DescriptorProperty
- cascade_iterator(type_, state, visited_instances=None, halt_on=None)¶
- inherited from the 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.
See PropertyLoader for the related instance implementation.
- class_attribute¶
- inherited from the class_attribute attribute of MapperProperty
Return the class-bound descriptor corresponding to this MapperProperty.
- compare(operator, value, **kw)¶
- inherited from the compare() method of MapperProperty
Return a compare operation for the columns represented by this MapperProperty to the given value, which may be a column value or an instance. ‘operator’ is an operator from the operators module, or from sql.Comparator.
By default uses the PropComparator attached to this MapperProperty under the attribute name “comparator”.
- create_row_processor(context, path, mapper, row, adapter)¶
- inherited from the create_row_processor() method of MapperProperty
Return a 3-tuple consisting of three row processing functions.
- do_init()¶
- inherited from the 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.
- info¶
- inherited from the info attribute of MapperProperty
Info dictionary associated with the object, allowing user-defined data to be associated with this MapperProperty.
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.
- init()¶
- inherited from the init() method of MapperProperty
Called after all mappers are created to assemble relationships between mappers and perform other post-mapper-creation initialization steps.
- is_primary()¶
- inherited from the is_primary() method of MapperProperty
Return True if this MapperProperty‘s mapper is the primary mapper for its class.
This flag is used to indicate that the MapperProperty can define attribute instrumentation for the class at the class level (as opposed to the individual instance level).
- merge(session, source_state, source_dict, dest_state, dest_dict, load, _recursive)¶
- inherited from the merge() method of MapperProperty
Merge the attribute represented by this MapperProperty from source to destination object
- post_instrument_class(mapper)¶
- inherited from the post_instrument_class() method of MapperProperty
Perform instrumentation adjustments that need to occur after init() has completed.
- setup(context, entity, path, adapter, **kwargs)¶
- inherited from the 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.
- class sqlalchemy.orm.query.QueryContext(query)¶
Bases: object
- class sqlalchemy.orm.attributes.QueryableAttribute(class_, key, impl=None, comparator=None, parententity=None, of_type=None)¶
Bases: sqlalchemy.orm.interfaces._MappedAttribute, sqlalchemy.orm.interfaces._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)¶
- inherited from the __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)¶
- inherited from the __le__() method of ColumnOperators
Implement the <= operator.
In a column context, produces the clause a <= b.
- __lt__(other)¶
- inherited from the __lt__() method of ColumnOperators
Implement the < operator.
In a column context, produces the clause a < b.
- __ne__(other)¶
- inherited from the __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.
- adapted(adapter)¶
- inherited from the adapted() method of PropComparator
Return a copy of this PropComparator which will use the given adaption function on the local side of generated expressions.
- any(criterion=None, **kwargs)¶
- inherited from the 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: - criterion – an optional ClauseElement formulated against the member class’ table or attributes.
- **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.
- asc()¶
- inherited from the asc() method of ColumnOperators
Produce a asc() clause against the parent object.
- between(cleft, cright)¶
- inherited from the between() method of ColumnOperators
Produce a between() clause against the parent object, given the lower and upper range.
- collate(collation)¶
- inherited from the collate() method of ColumnOperators
Produce a collate() clause against the parent object, given the collation string.
- concat(other)¶
- inherited from the 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)¶
- inherited from the contains() method of ColumnOperators
Implement the ‘contains’ operator.
In a column context, produces the clause LIKE '%<other>%'
- desc()¶
- inherited from the desc() method of ColumnOperators
Produce a desc() clause against the parent object.
- distinct()¶
- inherited from the distinct() method of ColumnOperators
Produce a distinct() clause against the parent object.
- endswith(other, **kwargs)¶
- inherited from the endswith() method of ColumnOperators
Implement the ‘endswith’ operator.
In a column context, produces the clause LIKE '%<other>'
- has(criterion=None, **kwargs)¶
- inherited from the 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: - criterion – an optional ClauseElement formulated against the member class’ table or attributes.
- **kwargs – key/value pairs corresponding to member class attribute names which will be compared via equality to the corresponding values.
- ilike(other, escape=None)¶
- inherited from the 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: - other – expression to be compared
- escape –
optional escape character, renders the ESCAPE keyword, e.g.:
somecolumn.ilike("foo/%bar", escape="/")
See also
- in_(other)¶
- inherited from the 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:
- If the attribute is a column-mapped property, i.e. 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.
- If the attribute is a 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 it’s own .info attribute (which should be the case, unless a user-defined SQL construct has defined one).
- If the attribute refers to any other kind of MapperProperty, including RelationshipProperty, the attribute will refer to the MapperProperty.info dictionary associated with that MapperProperty.
- To access the 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)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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: - other – expression to be compared
- escape –
optional escape character, renders the ESCAPE keyword, e.g.:
somecolumn.like("foo/%bar", escape="/")
See also
- match(other, **kwargs)¶
- inherited from the match() method of ColumnOperators
Implements the ‘match’ operator.
In a column context, this produces a MATCH clause, i.e. MATCH '<other>'. The allowed contents of other are database backend specific.
- notilike(other, escape=None)¶
- inherited from the 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)¶
- inherited from the 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)¶
- inherited from the 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()¶
- inherited from the nullsfirst() method of ColumnOperators
Produce a nullsfirst() clause against the parent object.
- nullslast()¶
- inherited from the nullslast() method of ColumnOperators
Produce a nullslast() clause against the parent object.
- op(opstring, precedence=0)¶
-
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: - operator – a string which will be output as the infix operator between this element and the expression passed to the generated function.
- precedence –
precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of 0 is lower than all operators except for the comma (,) and AS operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators.
New in version 0.8: - added the ‘precedence’ argument.
- 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)¶
- inherited from the startswith() method of ColumnOperators
Implement the startwith operator.
In a column context, produces the clause LIKE '<other>%'
