Class BindParameter

lib/sqlalchemy/sql/elements.py:2015–2305

r"""Represent a "bound expression". :class:`.BindParameter` is invoked explicitly using the :func:`.bindparam` function, as in:: from sqlalchemy import bindparam stmt = select(users_table).where( users_table.c.name == bindparam("username") ) Detail

class BindParameter(roles.InElementRole, KeyedColumnElement[_T]):
    r"""Represent a "bound expression".

    :class:`.BindParameter` is invoked explicitly using the
    :func:`.bindparam` function, as in::

        from sqlalchemy import bindparam

        stmt = select(users_table).where(
            users_table.c.name == bindparam("username")
        )

    Detailed discussion of how :class:`.BindParameter` is used is
    at :func:`.bindparam`.

    .. seealso::

        :func:`.bindparam`

    """

    __visit_name__ = "bindparam"

    _traverse_internals: _TraverseInternalsType = [
        ("key", InternalTraversal.dp_anon_name),
        ("type", InternalTraversal.dp_type),
        ("callable", InternalTraversal.dp_plain_dict),
        ("value", InternalTraversal.dp_plain_obj),
        ("literal_execute", InternalTraversal.dp_boolean),
    ]

    key: str
    _anon_map_key: Optional[str] = None
    type: TypeEngine[_T]
    value: Optional[_T]

    _is_crud = False
    _is_bind_parameter = True

    # bindparam implements its own _gen_cache_key() method however
    # we check subclasses for this flag, else no cache key is generated
    inherit_cache = True

    def __init__(
        self,
        key: Optional[str],
        value: Any = _NoArg.NO_ARG,
        type_: Optional[_TypeEngineArgument[_T]] = None,
        unique: bool = False,
        required: Union[bool, Literal[_NoArg.NO_ARG]] = _NoArg.NO_ARG,
        quote: Optional[bool] = None,
        callable_: Optional[Callable[[], Any]] = None,
        expanding: bool = False,
        isoutparam: bool = False,
        literal_execute: bool = False,
        _compared_to_operator: Optional[OperatorType] = None,
        _compared_to_type: Optional[TypeEngine[Any]] = None,
        _is_crud: bool = False,