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Classe « Enum »

Constructeur sqlalchemy.Enum.__init__

Signature de la constructeur __init__

def __init__(self, *enums: 'object', **kw: 'Any') 

Description

help(Enum.__init__)

Construct an enum.

Keyword arguments which don't apply to a specific backend are ignored
by that backend.

:param \*enums: either exactly one PEP-435 compliant enumerated type
   or one or more string labels.

:param create_constraint: defaults to False.  When creating a
   non-native enumerated type, also build a CHECK constraint on the
   database against the valid values.

   .. note:: it is strongly recommended that the CHECK constraint
      have an explicit name in order to support schema-management
      concerns.  This can be established either by setting the
      :paramref:`.Enum.name` parameter or by setting up an
      appropriate naming convention; see
      :ref:`constraint_naming_conventions` for background.

   .. versionchanged:: 1.4 - this flag now defaults to False, meaning
      no CHECK constraint is generated for a non-native enumerated
      type.

:param metadata: Associate this type directly with a ``MetaData``
   object. For types that exist on the target database as an
   independent schema construct (PostgreSQL), this type will be
   created and dropped within ``create_all()`` and ``drop_all()``
   operations. If the type is not associated with any ``MetaData``
   object, it will associate itself with each ``Table`` in which it is
   used, and will be created when any of those individual tables are
   created, after a check is performed for its existence. The type is
   only dropped when ``drop_all()`` is called for that ``Table``
   object's metadata, however.

   The value of the :paramref:`_schema.MetaData.schema` parameter of
   the :class:`_schema.MetaData` object, if set, will be used as the
   default value of the :paramref:`_types.Enum.schema` on this object
   if an explicit value is not otherwise supplied.

   .. versionchanged:: 1.4.12 :class:`_types.Enum` inherits the
      :paramref:`_schema.MetaData.schema` parameter of the
      :class:`_schema.MetaData` object if present, when passed using
      the :paramref:`_types.Enum.metadata` parameter.

:param name: The name of this type. This is required for PostgreSQL
   and any future supported database which requires an explicitly
   named type, or an explicitly named constraint in order to generate
   the type and/or a table that uses it. If a PEP-435 enumerated
   class was used, its name (converted to lower case) is used by
   default.

:param native_enum: Use the database's native ENUM type when
   available. Defaults to True. When False, uses VARCHAR + check
   constraint for all backends. When False, the VARCHAR length can be
   controlled with :paramref:`.Enum.length`; currently "length" is
   ignored if native_enum=True.

:param length: Allows specifying a custom length for the VARCHAR
   when a non-native enumeration datatype is used.  By default it uses
   the length of the longest value.

   .. versionchanged:: 2.0.0 The :paramref:`.Enum.length` parameter
      is used unconditionally for ``VARCHAR`` rendering regardless of
      the :paramref:`.Enum.native_enum` parameter, for those backends
      where ``VARCHAR`` is used for enumerated datatypes.


:param schema: Schema name of this type. For types that exist on the
   target database as an independent schema construct (PostgreSQL),
   this parameter specifies the named schema in which the type is
   present.

   If not present, the schema name will be taken from the
   :class:`_schema.MetaData` collection if passed as
   :paramref:`_types.Enum.metadata`, for a :class:`_schema.MetaData`
   that includes the :paramref:`_schema.MetaData.schema` parameter.

   .. versionchanged:: 1.4.12 :class:`_types.Enum` inherits the
      :paramref:`_schema.MetaData.schema` parameter of the
      :class:`_schema.MetaData` object if present, when passed using
      the :paramref:`_types.Enum.metadata` parameter.

   Otherwise, if the :paramref:`_types.Enum.inherit_schema` flag is set
   to ``True``, the schema will be inherited from the associated
   :class:`_schema.Table` object if any; when
   :paramref:`_types.Enum.inherit_schema` is at its default of
   ``False``, the owning table's schema is **not** used.


:param quote: Set explicit quoting preferences for the type's name.

:param inherit_schema: When ``True``, the "schema" from the owning
   :class:`_schema.Table`
   will be copied to the "schema" attribute of this
   :class:`.Enum`, replacing whatever value was passed for the
   ``schema`` attribute.   This also takes effect when using the
   :meth:`_schema.Table.to_metadata` operation.

:param validate_strings: when True, string values that are being
   passed to the database in a SQL statement will be checked
   for validity against the list of enumerated values.  Unrecognized
   values will result in a ``LookupError`` being raised.

:param values_callable: A callable which will be passed the PEP-435
   compliant enumerated type, which should then return a list of string
   values to be persisted. This allows for alternate usages such as
   using the string value of an enum to be persisted to the database
   instead of its name. The callable must return the values to be
   persisted in the same order as iterating through the Enum's
   ``__member__`` attribute. For example
   ``lambda x: [i.value for i in x]``.

   .. versionadded:: 1.2.3

:param sort_key_function: a Python callable which may be used as the
   "key" argument in the Python ``sorted()`` built-in.   The SQLAlchemy
   ORM requires that primary key columns which are mapped must
   be sortable in some way.  When using an unsortable enumeration
   object such as a Python 3 ``Enum`` object, this parameter may be
   used to set a default sort key function for the objects.  By
   default, the database value of the enumeration is used as the
   sorting function.

   .. versionadded:: 1.3.8

:param omit_aliases: A boolean that when true will remove aliases from
   pep 435 enums. defaults to ``True``.

   .. versionchanged:: 2.0 This parameter now defaults to True.

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