sqlalchemy.sql.schema.Index

class documentation

class Index(DialectKWArgs, ColumnCollectionMixin, 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 _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 .func construct in conjunction with table-bound _schema.Column objects:

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

An .Index can also be manually associated with a _schema.Table, either through inline declaration or using _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 _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)"))
        )

New in version 0.9.5: the _expression.text construct may be used to specify .Index expressions, provided the .Index is explicitly associated with the _schema.Table.

See Also

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

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

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

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

Method	`__init__`	Construct an index object.
Method	`__repr__`	Undocumented
Method	`_set_parent`	Associate with this SchemaEvent's parent object.
Method	`create`	Issue a `CREATE` statement for this `.Index`, using the given `.Connectable` for connectivity.
Method	`drop`	Issue a `DROP` statement for this `.Index`, using the given `.Connectable` for connectivity.
Class Variable	`__visit_name__`	Undocumented
Instance Variable	`expressions`	Undocumented
Instance Variable	`info`	Info dictionary associated with the object, allowing user-defined data to be associated with this `.SchemaItem`.
Instance Variable	`name`	Undocumented
Instance Variable	`table`	Undocumented
Instance Variable	`unique`	Undocumented
Property	`bind`	Return the connectable associated with this Index.

Inherited from DialectKWArgs:

Class Method	`argument_for`	Add a new kind of dialect-specific keyword argument for this class.
Method	`_kw_reg_for_dialect_cls`	Undocumented
Method	`_validate_dialect_kwargs`	Undocumented
Class Variable	`_dialect_kwargs_traverse_internals`	Undocumented
Class Variable	`_kw_registry`	Undocumented
Property	`dialect_kwargs`	A collection of keyword arguments specified as dialect-specific options to this construct.
Property	`dialect_options`	A collection of keyword arguments specified as dialect-specific options to this construct.
Property	`kwargs`	A synonym for `.DialectKWArgs.dialect_kwargs`.

Inherited from ColumnCollectionMixin:

Method	`_check_attach`	Undocumented
Method	`_col_expressions`	Undocumented
Class Variable	`_allow_multiple_tables`	Undocumented
Instance Variable	`_cols_wo_table`	Undocumented
Instance Variable	`_column_flag`	Undocumented
Instance Variable	`_pending_colargs`	Undocumented
Instance Variable	`columns`	A `_expression.ColumnCollection` of `_schema.Column` objects.

Inherited from SchemaItem:

Method	`_init_items`	Initialize the list of child items for this SchemaItem.
Method	`_schema_item_copy`	Undocumented
Class Variable	`_use_schema_map`	Undocumented
Class Variable	`create_drop_stringify_dialect`	Undocumented

Inherited from SchemaEventTarget (via SchemaItem):

Method _set_parent_with_dispatch Undocumented

Inherited from Traversible (via SchemaItem):

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

def __init__(self, name, *expressions, **kw):

overrides sqlalchemy.sql.schema.ColumnCollectionMixin.__init__

Construct an index object.

Parameters
name	The name of the index
*expressions	Column expressions to include in the index. The expressions are normally instances of `_schema.Column`, but may also be arbitrary SQL expressions which ultimately refer to a `_schema.Column`.
**kw	Additional keyword arguments not mentioned above are dialect specific, and passed in the form `<dialectname>_<argname>`. See the documentation regarding an individual dialect at :ref:`dialect_toplevel` for detail on documented arguments.
unique=False	Keyword only argument; if True, create a unique index.
quote=None	Keyword only argument; whether to apply quoting to the name of the index. Works in the same manner as that of :paramref:`_schema.Column.quote`.
info=None	Optional data dictionary which will be populated into the `.SchemaItem.info` attribute of this object. New in version 1.0.0.

def __repr__(self):

overrides sqlalchemy.sql.schema.SchemaItem.__repr__

Undocumented

def _set_parent(self, table, **kw):

overrides sqlalchemy.sql.schema.ColumnCollectionMixin._set_parent

Associate with this SchemaEvent's parent object.

def create(self, bind=None, checkfirst=False):

Issue a CREATE statement for this .Index, using the given .Connectable for connectivity.

Note

the "bind" argument will be required in SQLAlchemy 2.0.