Classe « quoted_name »

Informations générales

Héritage

builtins.object
    builtins.str
builtins.object
    MemoizedSlots
        quoted_name

Définition

class quoted_name(MemoizedSlots, builtins.str):

help(quoted_name)

Represent a SQL identifier combined with quoting preferences.

:class:`.quoted_name` is a Python unicode/str subclass which
represents a particular identifier name along with a
``quote`` flag.  This ``quote`` flag, when set to
``True`` or ``False``, overrides automatic quoting behavior
for this identifier in order to either unconditionally quote
or to not quote the name.  If left at its default of ``None``,
quoting behavior is applied to the identifier on a per-backend basis
based on an examination of the token itself.

A :class:`.quoted_name` object with ``quote=True`` is also
prevented from being modified in the case of a so-called
"name normalize" option.  Certain database backends, such as
Oracle Database, Firebird, and DB2 "normalize" case-insensitive names
as uppercase.  The SQLAlchemy dialects for these backends
convert from SQLAlchemy's lower-case-means-insensitive convention
to the upper-case-means-insensitive conventions of those backends.
The ``quote=True`` flag here will prevent this conversion from occurring
to support an identifier that's quoted as all lower case against
such a backend.

The :class:`.quoted_name` object is normally created automatically
when specifying the name for key schema constructs such as
:class:`_schema.Table`, :class:`_schema.Column`, and others.
The class can also be
passed explicitly as the name to any function that receives a name which
can be quoted.  Such as to use the :meth:`_engine.Engine.has_table`
method with
an unconditionally quoted name::

    from sqlalchemy import create_engine
    from sqlalchemy import inspect
    from sqlalchemy.sql import quoted_name

    engine = create_engine("oracle+oracledb://some_dsn")
    print(inspect(engine).has_table(quoted_name("some_table", True)))

The above logic will run the "has table" logic against the Oracle Database
backend, passing the name exactly as ``"some_table"`` without converting to
upper case.

.. versionchanged:: 1.2 The :class:`.quoted_name` construct is now
   importable from ``sqlalchemy.sql``, in addition to the previous
   location of ``sqlalchemy.sql.elements``.

Constructeur(s)

Signature du constructeur	Description
__new__(cls, value: 'str', quote: 'Optional[bool]') -> 'quoted_name'
__init__(self, /, args, *kwargs)	Initialize self. See help(type(self)) for accurate signature. _{[extrait de __init__.__doc__]}