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Module « sqlalchemy »

Classe « Index »

Informations générales

Héritage

    builtins.object
        Visitable
builtins.object
    EventTarget
        SchemaEventTarget
            SchemaItem
        builtins.object
            HasConditionalDDL
        builtins.object
            ColumnCollectionMixin
        builtins.object
            DialectKWArgs
                Index

Définition

class Index(DialectKWArgs, ColumnCollectionMixin, HasConditionalDDL, SchemaItem):

help(Index)

A table-level INDEX.

Defines a composite (one or more column) INDEX.

E.g.::

    sometable = Table(
        "sometable",
        metadata,
        Column("name", String(50)),
        Column("address", String(100)),
    )

    Index("some_index", sometable.c.name)

For a no-frills, single column index, adding
:class:`_schema.Column` also supports ``index=True``::

    sometable = Table(
        "sometable", metadata, Column("name", String(50), index=True)
    )

For a composite index, multiple columns can be specified::

    Index("some_index", sometable.c.name, sometable.c.address)

Functional indexes are supported as well, typically by using the
:data:`.func` construct in conjunction with table-bound
:class:`_schema.Column` objects::

    Index("some_index", func.lower(sometable.c.name))

An :class:`.Index` can also be manually associated with a
:class:`_schema.Table`,
either through inline declaration or using
:meth:`_schema.Table.append_constraint`.  When this approach is used,
the names
of the indexed columns can be specified as strings::

    Table(
        "sometable",
        metadata,
        Column("name", String(50)),
        Column("address", String(100)),
        Index("some_index", "name", "address"),
    )

To support functional or expression-based indexes in this form, the
:func:`_expression.text` construct may be used::

    from sqlalchemy import text

    Table(
        "sometable",
        metadata,
        Column("name", String(50)),
        Column("address", String(100)),
        Index("some_index", text("lower(name)")),
    )

.. seealso::

    :ref:`schema_indexes` - General information on :class:`.Index`.

    :ref:`postgresql_indexes` - PostgreSQL-specific options available for
    the :class:`.Index` construct.

    :ref:`mysql_indexes` - MySQL-specific options available for the
    :class:`.Index` construct.

    :ref:`mssql_indexes` - MSSQL-specific options available for the
    :class:`.Index` construct.

Constructeur(s)

Signature du constructeur	Description
__init__(self, name: 'Optional[str]', *expressions: '_DDLColumnArgument', unique: 'bool' = False, quote: 'Optional[bool]' = None, info: 'Optional[_InfoType]' = None, _table: 'Optional[Table]' = None, _column_flag: 'bool' = False, **dialect_kw: 'Any') -> 'None'	Construct an index object. [extrait de __init__.__doc__]

Liste des opérateurs

Opérateurs hérités de la classe object

__eq__, __ge__, __gt__, __le__, __lt__, __ne__

Méthodes héritées de la classe SchemaItem

__subclasshook__

Méthodes héritées de la classe Visitable

__class_getitem__, __init_subclass__

Méthodes héritées de la classe HasConditionalDDL

ddl_if

Méthodes héritées de la classe DialectKWArgs

argument_for

Méthodes héritées de la classe object

__delattr__, __dir__, __format__, __getattribute__, __getstate__, __hash__, __reduce__, __reduce_ex__, __setattr__, __sizeof__, __str__

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