Classe « JSON »

Constructeur sqlalchemy.JSON.__init__

Signature de la constructeur __init__

def __init__(self, none_as_null=False) 

Description

__init__.__doc__

Construct a :class:`_types.JSON` type.

        :param none_as_null=False: if True, persist the value ``None`` as a
         SQL NULL value, not the JSON encoding of ``null``.   Note that
         when this flag is False, the :func:`.null` construct can still
         be used to persist a NULL value::

             from sqlalchemy import null
             conn.execute(table.insert(), data=null())

         .. note::

              :paramref:`_types.JSON.none_as_null` does **not** apply to the
              values passed to :paramref:`_schema.Column.default` and
              :paramref:`_schema.Column.server_default`; a value of ``None``
              passed for these parameters means "no default present".

              Additionally, when used in SQL comparison expressions, the
              Python value ``None`` continues to refer to SQL null, and not
              JSON NULL.  The :paramref:`_types.JSON.none_as_null` flag refers
              explicitly to the **persistence** of the value within an
              INSERT or UPDATE statement.   The :attr:`_types.JSON.NULL`
              value should be used for SQL expressions that wish to compare to
              JSON null.

         .. seealso::

              :attr:`.types.JSON.NULL`