Module « sqlalchemy »

Classe « Unicode »

Informations générales

Héritage

builtins.object
    Traversible
        TypeEngine
    builtins.object
        Concatenable
            String
                Unicode

Définition

class Unicode(String):

Description _{[extrait de Unicode.__doc__]}

A variable length Unicode string type.

    The :class:`.Unicode` type is a :class:`.String` subclass that assumes
    input and output strings that may contain non-ASCII characters, and for
    some backends implies an underlying column type that is explicitly
    supporting of non-ASCII data, such as ``NVARCHAR`` on Oracle and SQL
    Server.  This will impact the output of ``CREATE TABLE`` statements and
    ``CAST`` functions at the dialect level, and also in some cases will
    indicate different behavior in the DBAPI itself in how it handles bound
    parameters.

    The character encoding used by the :class:`.Unicode` type that is used to
    transmit and receive data to the database is usually determined by the
    DBAPI itself. All modern DBAPIs accommodate non-ASCII strings but may have
    different methods of managing database encodings; if necessary, this
    encoding should be configured as detailed in the notes for the target DBAPI
    in the :ref:`dialect_toplevel` section.

    In modern SQLAlchemy, use of the :class:`.Unicode` datatype does not
    typically imply any encoding/decoding behavior within SQLAlchemy itself.
    Historically, when DBAPIs did not support Python ``unicode`` objects under
    Python 2, SQLAlchemy handled unicode encoding/decoding services itself
    which would be controlled by the flag :paramref:`.String.convert_unicode`;
    this flag is deprecated as it is no longer needed for Python 3.

    When using Python 2, data that is passed to columns that use the
    :class:`.Unicode` datatype must be of type ``unicode``, and not ``str``
    which in Python 2 is equivalent to ``bytes``.  In Python 3, all data
    passed to columns that use the :class:`.Unicode` datatype should be
    of type ``str``.   See the flag :paramref:`.String.convert_unicode` for
    more discussion of unicode encode/decode behavior under Python 2.

    .. warning:: Some database backends, particularly SQL Server with pyodbc,
       are known to have undesirable behaviors regarding data that is noted
       as being of ``NVARCHAR`` type as opposed to ``VARCHAR``, including
       datatype mismatch errors and non-use of indexes.  See the section
       on :meth:`.DialectEvents.do_setinputsizes` for background on working
       around unicode character issues for backends like SQL Server with
       pyodbc as well as cx_Oracle.

    .. seealso::

        :class:`.UnicodeText` - unlengthed textual counterpart
        to :class:`.Unicode`.

        :paramref:`.String.convert_unicode`

        :meth:`.DialectEvents.do_setinputsizes`


    

Constructeur(s)

Signature du constructeur	Description
__init__(self, length=None, **kwargs)

Liste des opérateurs

Opérateurs hérités de la classe object

__eq__, __ge__, __gt__, __le__, __lt__, __ne__

Méthodes héritées de la classe String

__init_subclass__, __subclasshook__, bind_processor, get_dbapi_type, literal_processor, result_processor

Méthodes héritées de la classe TypeEngine

__repr__, __str__, adapt, as_generic, bind_expression, coerce_compared_value, column_expression, Comparator, comparator_factory, compare_against_backend, compare_values, compile, copy, copy_value, dialect_impl, evaluates_none, with_variant

Méthodes héritées de la classe Traversible

__class_getitem__, get_children

Méthodes héritées de la classe object

__delattr__, __dir__, __format__, __getattribute__, __hash__, __reduce__, __reduce_ex__, __setattr__, __sizeof__