Classe « ForeignKey »

Constructeur sqlalchemy.ForeignKey.__init__

Signature de la constructeur __init__

def __init__(self, column, _constraint=None, use_alter=False, name=None, onupdate=None, ondelete=None, deferrable=None, initially=None, link_to_name=False, match=None, info=None, **dialect_kw) 

Description

__init__.__doc__

        Construct a column-level FOREIGN KEY.

        The :class:`_schema.ForeignKey` object when constructed generates a
        :class:`_schema.ForeignKeyConstraint`
        which is associated with the parent
        :class:`_schema.Table` object's collection of constraints.

        :param column: A single target column for the key relationship. A
            :class:`_schema.Column` object or a column name as a string:
            ``tablename.columnkey`` or ``schema.tablename.columnkey``.
            ``columnkey`` is the ``key`` which has been assigned to the column
            (defaults to the column name itself), unless ``link_to_name`` is
            ``True`` in which case the rendered name of the column is used.

        :param name: Optional string. An in-database name for the key if
            `constraint` is not provided.

        :param onupdate: Optional string. If set, emit ON UPDATE <value> when
            issuing DDL for this constraint. Typical values include CASCADE,
            DELETE and RESTRICT.

        :param ondelete: Optional string. If set, emit ON DELETE <value> when
            issuing DDL for this constraint. Typical values include CASCADE,
            DELETE and RESTRICT.

        :param deferrable: Optional bool. If set, emit DEFERRABLE or NOT
            DEFERRABLE when issuing DDL for this constraint.

        :param initially: Optional string. If set, emit INITIALLY <value> when
            issuing DDL for this constraint.

        :param link_to_name: if True, the string name given in ``column`` is
            the rendered name of the referenced column, not its locally
            assigned ``key``.

        :param use_alter: passed to the underlying
            :class:`_schema.ForeignKeyConstraint`
            to indicate the constraint should
            be generated/dropped externally from the CREATE TABLE/ DROP TABLE
            statement.  See :paramref:`_schema.ForeignKeyConstraint.use_alter`
            for further description.

            .. seealso::

                :paramref:`_schema.ForeignKeyConstraint.use_alter`

                :ref:`use_alter`

        :param match: Optional string. If set, emit MATCH <value> when issuing
            DDL for this constraint. Typical values include SIMPLE, PARTIAL
            and FULL.

        :param info: Optional data dictionary which will be populated into the
            :attr:`.SchemaItem.info` attribute of this object.

            .. versionadded:: 1.0.0

        :param \**dialect_kw:  Additional keyword arguments are dialect
            specific, and passed in the form ``<dialectname>_<argname>``.  The
            arguments are ultimately handled by a corresponding
            :class:`_schema.ForeignKeyConstraint`.
            See the documentation regarding
            an individual dialect at :ref:`dialect_toplevel` for detail on
            documented arguments.

            .. versionadded:: 0.9.2