Class Index

lib/sqlalchemy/sql/schema.py:5144–5355

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

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