Classe « FromClause »

Informations générales

Héritage

        builtins.object
            Visitable
                CompilerElement
        builtins.object
            Visitable
        builtins.object
            HasTraverseInternals
                ExternallyTraversible
        builtins.object
            HasTraverseInternals
                HasCopyInternals
        builtins.object
            HasMemoized
        builtins.object
            HasCacheKey
                MemoizedHasCacheKey
builtins.object
    Visitable
builtins.object
    HasTraverseInternals
        ExternallyTraversible
            SupportsAnnotations
                SupportsWrappingAnnotations
                    ClauseElement
                        DQLDMLClauseElement
                builtins.object
                    SQLRole
                        ReturnsRowsRole
                            ReturnsRows
                                Selectable
        builtins.object
            SQLRole
                StructuralRole
            builtins.object
                UsesInspection
            builtins.object
                AllowsLambdaRole
                    JoinTargetRole
        builtins.object
            SQLRole
                ColumnListRole
            builtins.object
                UsesInspection
            builtins.object
                AllowsLambdaRole
                    ColumnsClauseRole
                        FromClauseRole
                            StrictFromClauseRole
                                AnonymizedFromClauseRole
                                    FromClause

Définition

class FromClause(AnonymizedFromClauseRole, Selectable):

help(FromClause)

Represent an element that can be used within the ``FROM``
clause of a ``SELECT`` statement.

The most common forms of :class:`_expression.FromClause` are the
:class:`_schema.Table` and the :func:`_expression.select` constructs.  Key
features common to all :class:`_expression.FromClause` objects include:

* a :attr:`.c` collection, which provides per-name access to a collection
  of :class:`_expression.ColumnElement` objects.
* a :attr:`.primary_key` attribute, which is a collection of all those
  :class:`_expression.ColumnElement`
  objects that indicate the ``primary_key`` flag.
* Methods to generate various derivations of a "from" clause, including
  :meth:`_expression.FromClause.alias`,
  :meth:`_expression.FromClause.join`,
  :meth:`_expression.FromClause.select`.

Constructeur(s)

Signature du constructeur	Description
__init__(self, /, args, *kwargs)	Initialize self. See help(type(self)) for accurate signature. _{[extrait de __init__.__doc__]}

Liste des attributs statiques

Nom de l'attribut	Valeur
allows_lambda	True
c	<sqlalchemy.util.langhelpers._memoized_property object at 0x0000020D9F9374D0>
columns	<sqlalchemy.util.langhelpers._non_memoized_property object at 0x0000020D9F937590>
description	<sqlalchemy.util.langhelpers._non_memoized_property object at 0x0000020D9F937410>
entity_namespace	<sqlalchemy.util.langhelpers._non_memoized_property object at 0x0000020D9F9375F0>
exported_columns	<sqlalchemy.util.langhelpers._non_memoized_property object at 0x0000020D9F937470>
foreign_keys	<sqlalchemy.util.langhelpers._memoized_property object at 0x0000020D9F9376B0>
inherit_cache	None
is_clause_element	True
is_dml	False
is_selectable	True
named_with_column	False
primary_key	<sqlalchemy.util.langhelpers._memoized_property object at 0x0000020D9F937650>
schema	None
stringify_dialect	default
supports_execution	False
uses_inspection	True

Liste des propriétés

Nom de la propriété	Description
selectable

Propriétés héritées de la classe Selectable

entity_namespace, exported_columns

Liste des opérateurs

Opérateurs hérités de la classe ClauseElement

__invert__

Liste des opérateurs

Opérateurs hérités de la classe object

__eq__, __ge__, __gt__, __le__, __lt__, __ne__

Liste des méthodes

Toutes les méthodes Méthodes d'instance Méthodes statiques

Signature de la méthode	Description
alias(self, name: 'Optional[str]' = None, flat: 'bool' = False) -> 'NamedFromClause'	Return an alias of this :class:`_expression.FromClause`. _{[extrait de alias.__doc__]}
is_derived_from(self, fromclause: 'Optional[FromClause]') -> 'bool'	Return ``True`` if this :class:`_expression.FromClause` is _{[extrait de is_derived_from.__doc__]}
join(self, right: '_FromClauseArgument', onclause: 'Optional[_ColumnExpressionArgument[bool]]' = None, isouter: 'bool' = False, full: 'bool' = False) -> 'Join'	Return a :class:`_expression.Join` from this _{[extrait de join.__doc__]}
outerjoin(self, right: '_FromClauseArgument', onclause: 'Optional[_ColumnExpressionArgument[bool]]' = None, full: 'bool' = False) -> 'Join'	Return a :class:`_expression.Join` from this _{[extrait de outerjoin.__doc__]}
select(self) -> 'Select[Any]'	Return a SELECT of this :class:`_expression.FromClause`. _{[extrait de select.__doc__]}
tablesample(self, sampling: 'Union[float, Function[Any]]', name: 'Optional[str]' = None, seed: 'Optional[roles.ExpressionElementRole[Any]]' = None) -> 'TableSample'	Return a TABLESAMPLE alias of this :class:`_expression.FromClause`. _{[extrait de tablesample.__doc__]}