sqlalchemy.sql.selectable.Join

class documentation

class Join(roles.DMLTableRole, FromClause): (source)

Known subclasses: sqlalchemy.orm.util._ORMJoin

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Represent a ``JOIN`` construct between two :class:`_expression.FromClause` elements. The public constructor function for :class:`_expression.Join` is the module-level :func:`_expression.join()` function, as well as the :meth:`_expression.FromClause.join` method of any :class:`_expression.FromClause` (e.g. such as :class:`_schema.Table`). .. seealso:: :func:`_expression.join` :meth:`_expression.FromClause.join`

Method __init__ Construct a new :class:`_expression.Join`.
Method is_derived_from Return ``True`` if this :class:`_expression.FromClause` is 'derived' from the given ``FromClause``.
Method select Create a :class:`_expression.Select` from this :class:`_expression.Join`.
Method self_group Apply a 'grouping' to this :class:`_expression.ClauseElement`.
Class Variable __visit_name__ Undocumented
Instance Variable full Undocumented
Instance Variable isouter Undocumented
Instance Variable left Undocumented
Instance Variable onclause Undocumented
Instance Variable right Undocumented
Property description A brief description of this :class:`_expression.FromClause`.
Class Method _can_join Undocumented
Class Method _join_condition Create a join condition between two tables or selectables.
Class Method _joincond_scan_left_right Undocumented
Class Method _joincond_trim_constraints Undocumented
Method _anonymous_fromclause Undocumented
Method _copy_internals Reassign internal elements to be clones of themselves.
Method _match_primaries Undocumented
Method _populate_column_collection Called on subclasses to establish the .c collection.
Method _refresh_for_new_column Given a column added to the .c collection of an underlying selectable, produce the local version of that column, assuming this selectable ultimately should proxy this column.
Class Variable _is_join Undocumented
Class Variable _traverse_internals Undocumented
Property _from_objects Undocumented
Property _hide_froms Undocumented

Inherited from DMLTableRole:

Class Variable __slots__ Undocumented
Class Variable _role_name Undocumented

Inherited from FromClause (via DMLTableRole):

Method alias Return an alias of this :class:`_expression.FromClause`.
Method join Return a :class:`_expression.Join` from this :class:`_expression.FromClause` to another :class:`FromClause`.
Method outerjoin Return a :class:`_expression.Join` from this :class:`_expression.FromClause` to another :class:`FromClause`, with the "isouter" flag set to True.
Method tablesample Return a TABLESAMPLE alias of this :class:`_expression.FromClause`.
Class Variable is_selectable Undocumented
Class Variable named_with_column Undocumented
Class Variable schema Define the 'schema' attribute for this :class:`_expression.FromClause`.
Instance Variable foreign_keys Return the collection of :class:`_schema.ForeignKey` marker objects which this FromClause references.
Instance Variable primary_key Return the iterable collection of :class:`_schema.Column` objects which comprise the primary key of this :class:`_selectable.FromClause`.
Property c A synonym for :attr:`.FromClause.columns`
Property columns A named-based collection of :class:`_expression.ColumnElement` objects maintained by this :class:`_expression.FromClause`.
Property entity_namespace Return a namespace used for name-based access in SQL expressions.
Property exported_columns A :class:`_expression.ColumnCollection` that represents the "exported" columns of this :class:`_expression.Selectable`.
Method _generate_fromclause_column_proxies Populate columns into an :class:`.AliasedReturnsRows` object.
Method _init_collections Undocumented
Method _is_lexical_equivalent Return ``True`` if this :class:`_expression.FromClause` and the other represent the same lexical identity.
Method _reset_column_collection Reset the attributes linked to the ``FromClause.c`` attribute.
Class Variable _is_clone_of Undocumented
Class Variable _is_from_clause Undocumented
Class Variable _use_schema_map Undocumented
Instance Variable _columns Undocumented
Property _cols_populated Undocumented
Property _select_iterable Undocumented

Inherited from FromClauseRole (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole):

Class Variable _is_subquery Undocumented

Inherited from AllowsLambdaRole (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole):

Class Variable allows_lambda Undocumented

Inherited from UsesInspection (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole):

Class Variable uses_inspection Undocumented
Class Variable _post_inspect Undocumented

Inherited from Selectable (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole):

Method corresponding_column Given a :class:`_expression.ColumnElement`, return the exported :class:`_expression.ColumnElement` object from the :attr:`_expression.Selectable.exported_columns` collection of this :class:`_expression...
Method lateral Return a LATERAL alias of this :class:`_expression.Selectable`.
Method replace_selectable Replace all occurrences of :class:`_expression.FromClause` 'old' with the given :class:`_expression.Alias` object, returning a copy of this :class:`_expression.FromClause`.

Inherited from ReturnsRows (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole, Selectable):

Property selectable Undocumented
Class Variable _is_lateral Undocumented
Class Variable _is_returns_rows Undocumented
Class Variable _is_select_base Undocumented
Class Variable _is_select_statement Undocumented
Property _all_selected_columns A sequence of column expression objects that represents the "selected" columns of this :class:`_expression.ReturnsRows`.

Inherited from DQLDMLClauseElement (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole, Selectable, ReturnsRows, ReturnsRowsRole, SQLRole):

Method compile Compile this SQL expression.
Method _compiler Return a compiler appropriate for this ClauseElement, given a Dialect.

Inherited from ClauseElement (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole, Selectable, ReturnsRows, ReturnsRowsRole, SQLRole, DQLDMLClauseElement):

Method __bool__ Undocumented
Method __getstate__ Undocumented
Method __invert__ Undocumented
Method __repr__ Undocumented
Method compare Compare this :class:`_expression.ClauseElement` to the given :class:`_expression.ClauseElement`.
Method get_children Return immediate child :class:`.visitors.HasTraverseInternals` elements of this :class:`.visitors.HasTraverseInternals`.
Method params Return a copy with :func:`_expression.bindparam` elements replaced.
Method unique_params Return a copy with :func:`_expression.bindparam` elements replaced.
Class Variable is_clause_element Undocumented
Class Variable is_dml Undocumented
Class Variable negation_clause 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 _execute_on_connection Undocumented
Method _execute_on_scalar an additional hook for subclasses to provide a different implementation for connection.scalar() vs. connection.execute().
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 :class:`_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 _gen_static_annotations_cache_key Undocumented
Class Variable _is_bind_parameter Undocumented
Class Variable _is_clause_list Undocumented
Class Variable _is_column_element Undocumented
Class Variable _is_from_container Undocumented
Class Variable _is_immutable Undocumented
Class Variable _is_keyed_column_element Undocumented
Class Variable _is_lambda_element Undocumented
Class Variable _is_select_container Undocumented
Class Variable _is_singleton_constant Undocumented
Class Variable _is_star Undocumented
Class Variable _is_table Undocumented
Class Variable _is_text_clause Undocumented
Class Variable _is_textual 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 _order_by_label_element Undocumented

Inherited from SupportsWrappingAnnotations (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole, Selectable, ReturnsRows, ReturnsRowsRole, SQLRole, DQLDMLClauseElement, ClauseElement):

Method _annotate return a copy of this ClauseElement with annotations updated by the given dictionary.
Method _deannotate return a copy of this :class:`_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 DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole, Selectable, ReturnsRows, ReturnsRowsRole, SQLRole, DQLDMLClauseElement, ClauseElement, SupportsWrappingAnnotations):

Class Variable proxy_set Undocumented
Method _gen_annotations_cache_key Undocumented
Property _annotations_cache_key Undocumented

Inherited from MemoizedHasCacheKey (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole, Selectable, ReturnsRows, ReturnsRowsRole, SQLRole, DQLDMLClauseElement, ClauseElement, SupportsWrappingAnnotations, SupportsAnnotations):

Method _generate_cache_key return a cache key.

Inherited from HasCacheKey (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole, Selectable, ReturnsRows, ReturnsRowsRole, SQLRole, DQLDMLClauseElement, ClauseElement, SupportsWrappingAnnotations, SupportsAnnotations, MemoizedHasCacheKey):

Class Variable inherit_cache Indicate if this :class:`.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
Method _gen_cache_key return an optional cache key.
Class Variable _generated_cache_key_traversal 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 CompilerElement (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole, Selectable, ReturnsRows, ReturnsRowsRole, SQLRole, DQLDMLClauseElement, ClauseElement, SupportsWrappingAnnotations, SupportsAnnotations, MemoizedHasCacheKey, HasCacheKey, HasCopyInternals, ExternallyTraversible, HasTraverseInternals):

Method __str__ Undocumented
Class Variable stringify_dialect Undocumented
Class Variable supports_execution Undocumented

Inherited from Visitable (via DMLTableRole, FromClause, AnonymizedFromClauseRole, StrictFromClauseRole, FromClauseRole, ColumnsClauseRole, JoinTargetRole, AllowsLambdaRole, UsesInspection, ColumnListRole, StructuralRole, Selectable, ReturnsRows, ReturnsRowsRole, SQLRole, DQLDMLClauseElement, ClauseElement, SupportsWrappingAnnotations, SupportsAnnotations, MemoizedHasCacheKey, HasCacheKey, HasCopyInternals, ExternallyTraversible, HasTraverseInternals, CompilerElement):

Method __class_getitem__ Undocumented
Method __init_subclass__ Undocumented
Class Method _generate_compiler_dispatch Undocumented
Method _compiler_dispatch Undocumented
Class Variable _original_compiler_dispatch Undocumented
def __init__(self, left: _FromClauseArgument, right: _FromClauseArgument, onclause: Optional[_OnClauseArgument] = None, isouter: bool = False, full: bool = False): (source)
overridden in sqlalchemy.orm.util._ORMJoin

Construct a new :class:`_expression.Join`. The usual entrypoint here is the :func:`_expression.join` function or the :meth:`_expression.FromClause.join` method of any :class:`_expression.FromClause` object.

def is_derived_from(self, fromclause: Optional[FromClause]) -> bool: (source)
overrides sqlalchemy.sql.selectable.FromClause.is_derived_from

Return ``True`` if this :class:`_expression.FromClause` is 'derived' from the given ``FromClause``. An example would be an Alias of a Table is derived from that Table.

def select(self) -> Select[Any]: (source)
overrides sqlalchemy.sql.selectable.FromClause.select

Create a :class:`_expression.Select` from this :class:`_expression.Join`. E.g.:: stmt = table_a.join(table_b, table_a.c.id == table_b.c.a_id) stmt = stmt.select() The above will produce a SQL string resembling:: SELECT table_a.id, table_a.col, table_b.id, table_b.a_id FROM table_a JOIN table_b ON table_a.id = table_b.a_id

def self_group(self, against: Optional[OperatorType] = None) -> FromGrouping: (source)
overrides sqlalchemy.sql.selectable.FromClause.self_group

Apply a 'grouping' to this :class:`_expression.ClauseElement`. This method is overridden by subclasses to return a "grouping" construct, i.e. parenthesis. In particular it's used by "binary" expressions to provide a grouping around themselves when placed into a larger expression, as well as by :func:`_expression.select` constructs when placed into the FROM clause of another :func:`_expression.select`. (Note that subqueries should be normally created using the :meth:`_expression.Select.alias` method, as many platforms require nested SELECT statements to be named). As expressions are composed together, the application of :meth:`self_group` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy's clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like ``x OR (y AND z)`` - AND takes precedence over OR. The base :meth:`self_group` method of :class:`_expression.ClauseElement` just returns self.

__visit_name__: str = (source)
overrides sqlalchemy.sql.selectable.FromClause.__visit_name__

Undocumented

full = (source)

Undocumented

isouter = (source)

Undocumented

left = (source)

Undocumented

onclause = (source)
overridden in sqlalchemy.orm.util._ORMJoin

Undocumented

right = (source)

Undocumented

@util.ro_non_memoized_property
description: str = (source)
overrides sqlalchemy.sql.selectable.FromClause.description

A brief description of this :class:`_expression.FromClause`. Used primarily for error message formatting.

@classmethod
def _can_join(cls, left: FromClause, right: FromClause, *, consider_as_foreign_keys: Optional[AbstractSet[ColumnClause[Any]]] = None) -> bool: (source)

Undocumented

@classmethod
def _join_condition(cls, a: FromClause, b: FromClause, *, a_subset: Optional[FromClause] = None, consider_as_foreign_keys: Optional[AbstractSet[ColumnClause[Any]]] = None) -> ColumnElement[bool]: (source)

Create a join condition between two tables or selectables. See sqlalchemy.sql.util.join_condition() for full docs.

@classmethod
@util.preload_module('sqlalchemy.sql.util')
def _joincond_scan_left_right(cls, a: FromClause, a_subset: Optional[FromClause], b: FromClause, consider_as_foreign_keys: Optional[AbstractSet[ColumnClause[Any]]]) -> collections.defaultdict[Optional[ForeignKeyConstraint], List[Tuple[ColumnClause[Any], ColumnClause[Any]]]]: (source)

Undocumented

@classmethod
def _joincond_trim_constraints(cls, a: FromClause, b: FromClause, constraints: Dict[Any, Any], consider_as_foreign_keys: Optional[Any]): (source)

Undocumented

@util.preload_module('sqlalchemy.sql.util')
def _anonymous_fromclause(self, name: Optional[str] = None, flat: bool = False) -> TODO_Any: (source)
overrides sqlalchemy.sql.selectable.FromClause._anonymous_fromclause

Undocumented

def _copy_internals(self, clone: _CloneCallableType = _clone, **kw: Any): (source)
overrides sqlalchemy.sql.traversals.HasCopyInternals._copy_internals

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 _match_primaries(self, left: FromClause, right: FromClause) -> ColumnElement[bool]: (source)

Undocumented

@util.preload_module('sqlalchemy.sql.util')
def _populate_column_collection(self): (source)
overrides sqlalchemy.sql.selectable.FromClause._populate_column_collection

Called on subclasses to establish the .c collection. Each implementation has a different way of establishing this collection.

def _refresh_for_new_column(self, column: ColumnElement[Any]): (source)
overrides sqlalchemy.sql.selectable.FromClause._refresh_for_new_column

Given a column added to the .c collection of an underlying selectable, produce the local version of that column, assuming this selectable ultimately should proxy this column. this is used to "ping" a derived selectable to add a new column to its .c. collection when a Column has been added to one of the Table objects it ultimately derives from. If the given selectable hasn't populated its .c. collection yet, it should at least pass on the message to the contained selectables, but it will return None. This method is currently used by Declarative to allow Table columns to be added to a partially constructed inheritance mapping that may have already produced joins. The method isn't public right now, as the full span of implications and/or caveats aren't yet clear. It's also possible that this functionality could be invoked by default via an event, which would require that selectables maintain a weak referencing collection of all derivations.

_is_join: bool = (source)
overrides sqlalchemy.sql.selectable.FromClause._is_join

Undocumented

_traverse_internals: _TraverseInternalsType = (source)
overrides sqlalchemy.sql.visitors.HasTraverseInternals._traverse_internals

Undocumented

@util.ro_non_memoized_property
_from_objects: List[FromClause] = (source)
overrides sqlalchemy.sql.elements.ClauseElement._from_objects

Undocumented

@util.ro_non_memoized_property
_hide_froms: Iterable[FromClause] = (source)
overrides sqlalchemy.sql.selectable.FromClause._hide_froms

Undocumented