sqlalchemy.sql.schema.Identity

class documentation

class Identity(IdentityOptions, FetchedValue, SchemaItem):

Defines an identity column, i.e. "GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY" syntax.

The .Identity construct is an inline construct added to the argument list of a _schema.Column object:

from sqlalchemy import Identity

Table('foo', metadata_obj,
    Column('id', Integer, Identity())
    Column('description', Text),
)

See the linked documentation below for complete details.

New in version 1.4.

See Also

:ref:`identity_ddl`

Method	`__init__`	Construct a GENERATED { ALWAYS \| BY DEFAULT } AS IDENTITY DDL construct to accompany a `_schema.Column`.
Method	`_as_for_update`	Undocumented
Method	`_copy`	Undocumented
Method	`_set_parent`	Associate with this SchemaEvent's parent object.
Method	`copy`	Undocumented
Class Variable	`__visit_name__`	Undocumented
Instance Variable	`always`	Undocumented
Instance Variable	`column`	Undocumented
Instance Variable	`on_null`	Undocumented

Inherited from IdentityOptions:

Instance Variable	`cache`	Undocumented
Instance Variable	`cycle`	Undocumented
Instance Variable	`increment`	Undocumented
Instance Variable	`maxvalue`	Undocumented
Instance Variable	`minvalue`	Undocumented
Instance Variable	`nomaxvalue`	Undocumented
Instance Variable	`nominvalue`	Undocumented
Instance Variable	`order`	Undocumented
Instance Variable	`start`	Undocumented

Inherited from FetchedValue:

Method	`__repr__`	Undocumented
Method	`_clone`	Undocumented
Class Variable	`has_argument`	Undocumented
Class Variable	`is_clause_element`	Undocumented
Class Variable	`is_server_default`	Undocumented
Class Variable	`reflected`	Undocumented
Instance Variable	`for_update`	Undocumented

Inherited from SchemaEventTarget (via FetchedValue):

Method _set_parent_with_dispatch Undocumented

Inherited from SchemaItem:

Method	`__repr__`	Undocumented
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
Property	`info`	Info dictionary associated with the object, allowing user-defined data to be associated with this `.SchemaItem`.

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, always=False, on_null=None, start=None, increment=None, minvalue=None, maxvalue=None, nominvalue=None, nomaxvalue=None, cycle=None, cache=None, order=None):

overrides sqlalchemy.sql.schema.IdentityOptions.__init__

Construct a GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY DDL construct to accompany a _schema.Column.

See the .Sequence documentation for a complete description of most parameters.

Note

MSSQL supports this construct as the preferred alternative to generate an IDENTITY on a column, but it uses non standard syntax that only support :paramref:`_schema.Identity.start` and :paramref:`_schema.Identity.increment`. All other parameters are ignored.

Parameters
always	A boolean, that indicates the type of identity column. If `False` is specified, the default, then the user-specified value takes precedence. If `True` is specified, a user-specified value is not accepted ( on some backends, like PostgreSQL, OVERRIDING SYSTEM VALUE, or similar, may be specified in an INSERT to override the sequence value). Some backends also have a default value for this parameter, `None` can be used to omit rendering this part in the DDL. It will be treated as `False` if a backend does not have a default value.
on_null	Set to `True` to specify ON NULL in conjunction with a `always=False` identity column. This option is only supported on some backends, like Oracle.
start	the starting index of the sequence.
increment	the increment value of the sequence.
minvalue	the minimum value of the sequence.
maxvalue	the maximum value of the sequence.
nominvalue	no minimum value of the sequence.
nomaxvalue	no maximum value of the sequence.
cycle	allows the sequence to wrap around when the maxvalue or minvalue has been reached.
cache	optional integer value; number of future values in the sequence which are calculated in advance.
order	optional boolean value; if true, renders the ORDER keyword.

def _as_for_update(self, for_update):

overrides sqlalchemy.sql.schema.FetchedValue._as_for_update

Undocumented

def _copy(self, **kw):

Undocumented

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

overrides sqlalchemy.sql.schema.FetchedValue._set_parent

Associate with this SchemaEvent's parent object.

@util.deprecated('1.4', 'The :meth:`_schema.Identity.copy` method is deprecated and will be removed in a future release.')
def copy(self, **kw):

Undocumented

__visit_name__: str =

overrides sqlalchemy.sql.schema.SchemaItem.__visit_name__

Undocumented

always =

Undocumented

column =

overrides sqlalchemy.sql.schema.FetchedValue.column

Undocumented

on_null =

Undocumented