sqlalchemy.sql.sqltypes.Enum

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. .. versionadded:: 1.1 a PEP-435 style enumerated class may be passed. :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. .. versionadded:: 1.1.0b2 :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. .. 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.

Undocumented

Produce an "adapted" form of this type, given an "impl" class to work with. This method is used internally to associate generic types with "implementation" types that are specific to a particular dialect.

Given an impl class, adapt this type to the impl assuming "emulated". The impl should also be an "emulated" version of this type, most likely the same class as this type itself. e.g.: sqltypes.Enum adapts to the Enum class.

Return an instance of the generic type corresponding to this type using heuristic rule. The method may be overridden if this heuristic rule is not sufficient. >>> from sqlalchemy.dialects.mysql import INTEGER >>> INTEGER(display_width=4).as_generic() Integer() >>> from sqlalchemy.dialects.mysql import NVARCHAR >>> NVARCHAR(length=100).as_generic() Unicode(length=100) .. versionadded:: 1.4.0b2 .. seealso:: :ref:`metadata_reflection_dbagnostic_types` - describes the use of :meth:`_types.TypeEngine.as_generic` in conjunction with the :meth:`_sql.DDLEvents.column_reflect` event, which is its intended use.

Return a conversion function for processing bind values. Returns a callable which will receive a bind parameter value as the sole positional argument and will return a value to send to the DB-API. If processing is not necessary, the method should return ``None``. .. note:: This method is only called relative to a **dialect specific type object**, which is often **private to a dialect in use** and is not the same type object as the public facing one, which means it's not feasible to subclass a :class:`.types.TypeEngine` class in order to provide an alternate :meth:`_types.TypeEngine.bind_processor` method, unless subclassing the :class:`_types.UserDefinedType` class explicitly. To provide alternate behavior for :meth:`_types.TypeEngine.bind_processor`, implement a :class:`_types.TypeDecorator` class and provide an implementation of :meth:`_types.TypeDecorator.process_bind_param`. .. seealso:: :ref:`types_typedecorator` :param dialect: Dialect instance in use.

Undocumented

Return a conversion function for processing literal values that are to be rendered directly without using binds. This function is used when the compiler makes use of the "literal_binds" flag, typically used in DDL generation as well as in certain scenarios where backends don't accept bound parameters. Returns a callable which will receive a literal Python value as the sole positional argument and will return a string representation to be rendered in a SQL statement. .. note:: This method is only called relative to a **dialect specific type object**, which is often **private to a dialect in use** and is not the same type object as the public facing one, which means it's not feasible to subclass a :class:`.types.TypeEngine` class in order to provide an alternate :meth:`_types.TypeEngine.literal_processor` method, unless subclassing the :class:`_types.UserDefinedType` class explicitly. To provide alternate behavior for :meth:`_types.TypeEngine.literal_processor`, implement a :class:`_types.TypeDecorator` class and provide an implementation of :meth:`_types.TypeDecorator.process_literal_param`. .. seealso:: :ref:`types_typedecorator`

Return a conversion function for processing result row values. Returns a callable which will receive a result row column value as the sole positional argument and will return a value to return to the user. If processing is not necessary, the method should return ``None``. .. note:: This method is only called relative to a **dialect specific type object**, which is often **private to a dialect in use** and is not the same type object as the public facing one, which means it's not feasible to subclass a :class:`.types.TypeEngine` class in order to provide an alternate :meth:`_types.TypeEngine.result_processor` method, unless subclassing the :class:`_types.UserDefinedType` class explicitly. To provide alternate behavior for :meth:`_types.TypeEngine.result_processor`, implement a :class:`_types.TypeDecorator` class and provide an implementation of :meth:`_types.TypeDecorator.process_result_value`. .. seealso:: :ref:`types_typedecorator` :param dialect: Dialect instance in use. :param coltype: DBAPI coltype argument received in cursor.description.