sqlalchemy.sql.expression.LambdaElement

class documentation

class LambdaElement(elements.ClauseElement):

Known subclasses: sqlalchemy.sql.expression.StatementLambdaElement, sqlalchemy.sql.lambdas.DeferredLambdaElement

A SQL construct where the state is stored as an un-invoked lambda.

The _sql.LambdaElement is produced transparently whenever passing lambda expressions into SQL constructs, such as:

stmt = select(table).where(lambda: table.c.col == parameter)

The _sql.LambdaElement is the base of the _sql.StatementLambdaElement which represents a full statement within a lambda.

New in version 1.4.

See Also

:ref:`engine_lambda_caching`

Method	`__getattr__`	Undocumented
Method	`__init__`	Undocumented
Method	`__repr__`	Undocumented
Method	`_copy_internals`	Reassign internal elements to be clones of themselves.
Method	`_gen_cache_key`	return an optional cache key.
Method	`_invoke_user_fn`	Undocumented
Method	`_param_dict`	Undocumented
Method	`_retrieve_tracker_rec`	Undocumented
Method	`_setup_binds_for_tracked_expr`	Undocumented
Class Variable	`__visit_name__`	Undocumented
Class Variable	`_is_lambda_element`	Undocumented
Class Variable	`_transforms`	Undocumented
Class Variable	`_traverse_internals`	Undocumented
Class Variable	`parent_lambda`	Undocumented
Instance Variable	`_rec`	Undocumented
Instance Variable	`_resolved_bindparams`	Undocumented
Instance Variable	`closure_cache_key`	Undocumented
Instance Variable	`fn`	Undocumented
Instance Variable	`opts`	Undocumented
Instance Variable	`role`	Undocumented
Instance Variable	`tracker_key`	Undocumented
Property	`_from_objects`	Undocumented
Property	`_is_sequence`	Undocumented
Property	`_resolved`	Undocumented
Property	`_select_iterable`	Undocumented

Inherited from ClauseElement:

Method	`compare`	Compare this `_expression.ClauseElement` to the given `_expression.ClauseElement`.
Method	`compile`	Compile this SQL expression.
Method	`params`	Return a copy with `_expression.bindparam` elements replaced.
Method	`self_group`	Apply a 'grouping' to this `_expression.ClauseElement`.
Method	`unique_params`	Return a copy with `_expression.bindparam` elements replaced.
Method	`__bool__`	Undocumented
Method	`__getstate__`	Undocumented
Method	`__invert__`	Undocumented
Method	`__str__`	Undocumented
Method	`_clone`	Create a shallow copy of this ClauseElement.
Method	`_cloned_set`	Return the set consisting all cloned ancestors of this ClauseElement.
Method	`_compile_w_cache`	Undocumented
Method	`_compiler`	Return a compiler appropriate for this ClauseElement, given a Dialect.
Method	`_execute_on_connection`	Undocumented
Method	`_negate`	Undocumented
Method	`_negate_in_binary`	a hook to allow the right side of a binary expression to respond to a negation of the binary expression.
Method	`_replace_params`	Undocumented
Method	`_set_propagate_attrs`	Undocumented
Method	`_ungroup`	Return this `_expression.ClauseElement` without any groupings.
Method	`_with_binary_element_type`	in the context of binary expression, convert the type of this object to the one given.
Class Variable	`_cache_key_traversal`	Undocumented
Class Variable	`_is_bind_parameter`	Undocumented
Class Variable	`_is_clause_list`	Undocumented
Class Variable	`_is_clone_of`	Undocumented
Class Variable	`_is_from_clause`	Undocumented
Class Variable	`_is_from_container`	Undocumented
Class Variable	`_is_immutable`	Undocumented
Class Variable	`_is_returns_rows`	Undocumented
Class Variable	`_is_select_container`	Undocumented
Class Variable	`_is_select_statement`	Undocumented
Class Variable	`_is_singleton_constant`	Undocumented
Class Variable	`_is_text_clause`	Undocumented
Class Variable	`_is_textual`	Undocumented
Class Variable	`_order_by_label_element`	Undocumented
Class Variable	`bind`	Undocumented
Class Variable	`description`	Undocumented
Class Variable	`is_clause_element`	Undocumented
Class Variable	`is_selectable`	Undocumented
Class Variable	`stringify_dialect`	Undocumented
Class Variable	`supports_execution`	Undocumented
Instance Variable	`_propagate_attrs`	like annotations, however these propagate outwards liberally as SQL constructs are built, and are set up at construction time.
Property	`_constructor`	return the 'constructor' for this ClauseElement.
Property	`entity_namespace`	Undocumented

Inherited from SQLRole (via ClauseElement):

Class Variable	`allows_lambda`	Undocumented
Class Variable	`uses_inspection`	Undocumented

Inherited from SupportsWrappingAnnotations (via ClauseElement):

Method	`_annotate`	return a copy of this ClauseElement with annotations updated by the given dictionary.
Method	`_deannotate`	return a copy of this `_expression.ClauseElement` with annotations removed.
Method	`_with_annotations`	return a copy of this ClauseElement with annotations replaced by the given dictionary.

Inherited from SupportsAnnotations (via ClauseElement, SupportsWrappingAnnotations):

Property _annotations_cache_key Undocumented

Inherited from MemoizedHasCacheKey (via ClauseElement):

Method _generate_cache_key return a cache key.

Inherited from HasCacheKey (via ClauseElement, MemoizedHasCacheKey):

Class Variable	`inherit_cache`	Indicate if this `.HasCacheKey` instance should make use of the cache key generation scheme used by its immediate superclass.
Class Method	`_generate_cache_attrs`	generate cache key dispatcher for a new class.
Class Method	`_generate_cache_key_for_object`	Undocumented
Class Variable	`__slots__`	Undocumented
Class Variable	`_hierarchy_supports_caching`	private attribute which may be set to False to prevent the inherit_cache warning from being emitted for a hierarchy of subclasses.
Class Variable	`_is_has_cache_key`	Undocumented

Inherited from Traversible (via ClauseElement):

Method	`get_children`	Return immediate child `.visitors.Traversible` elements of this `.visitors.Traversible`.
Method	`__class_getitem__`	Undocumented

def __getattr__(self, key):

Undocumented

def __init__(self, fn, role, opts=LambdaOptions, apply_propagate_attrs=None):

overridden in sqlalchemy.sql.lambdas.DeferredLambdaElement, sqlalchemy.sql.lambdas.LinkedLambdaElement

Undocumented

def __repr__(self):

overrides sqlalchemy.sql.expression.ClauseElement.__repr__

Undocumented

def _copy_internals(self, clone=_clone, deferred_copy_internals=None, **kw):

overrides sqlalchemy.sql.traversals.HasCopyInternals._copy_internals

overridden in sqlalchemy.sql.lambdas.DeferredLambdaElement

Reassign internal elements to be clones of themselves.

Called during a copy-and-traverse operation on newly shallow-copied elements to create a deep copy.

The given clone function should be used, which may be applying additional transformations to the element (i.e. replacement traversal, cloned traversal, annotations).

def _gen_cache_key(self, anon_map, bindparams):

overrides sqlalchemy.sql.traversals.HasCacheKey._gen_cache_key

return an optional cache key.

The cache key is a tuple which can contain any series of objects that are hashable and also identifies this object uniquely within the presence of a larger SQL expression or statement, for the purposes of caching the resulting query.

The cache key should be based on the SQL compiled structure that would ultimately be produced. That is, two structures that are composed in exactly the same way should produce the same cache key; any difference in the structures that would affect the SQL string or the type handlers should result in a different cache key.

If a structure cannot produce a useful cache key, the NO_CACHE symbol should be added to the anon_map and the method should return None.

def _invoke_user_fn(self, fn, *arg):

overridden in sqlalchemy.sql.lambdas.DeferredLambdaElement, sqlalchemy.sql.lambdas.LinkedLambdaElement

Undocumented

def _param_dict(self):

Undocumented

def _retrieve_tracker_rec(self, fn, apply_propagate_attrs, opts):

Undocumented

def _setup_binds_for_tracked_expr(self, expr):

Undocumented

__visit_name__: str =

overrides sqlalchemy.sql.expression.ClauseElement.__visit_name__

Undocumented

_is_lambda_element: bool =

overrides sqlalchemy.sql.expression.ClauseElement._is_lambda_element

Undocumented

_transforms: tuple =

Undocumented

_traverse_internals =

Undocumented

parent_lambda =

overridden in sqlalchemy.sql.lambdas.LinkedLambdaElement

Undocumented

_rec =

Undocumented

_resolved_bindparams: list =

Undocumented

closure_cache_key =

Undocumented

fn =

overridden in sqlalchemy.sql.lambdas.LinkedLambdaElement

Undocumented

opts =

overridden in sqlalchemy.sql.lambdas.LinkedLambdaElement

Undocumented

role =

overridden in sqlalchemy.sql.lambdas.LinkedLambdaElement

Undocumented

tracker_key =

overridden in sqlalchemy.sql.lambdas.LinkedLambdaElement

Undocumented

@property
_from_objects =

overrides sqlalchemy.sql.expression.ClauseElement._from_objects

Undocumented

@property
_is_sequence =

Undocumented

@util.memoized_property
_resolved =

Undocumented

@property
_select_iterable =

Undocumented