expression.py 文件源码

def column(text, type_=None):
    """Return a textual column clause, as would be in the columns clause of a
    ``SELECT`` statement.

    The object returned is an instance of :class:`.ColumnClause`, which
    represents the "syntactical" portion of the schema-level
    :class:`~sqlalchemy.schema.Column` object.  It is often used directly
    within :func:`~.expression.select` constructs or with lightweight
    :func:`~.expression.table` constructs.

    Note that the :func:`~.expression.column` function is not part of
    the ``sqlalchemy`` namespace.  It must be imported from the
    ``sql`` package::

        from sqlalchemy.sql import table, column

    :param text: the name of the column.  Quoting rules will be applied
      to the clause like any other column name. For textual column constructs
      that are not to be quoted, use the :func:`literal_column` function.

    :param type\_: an optional :class:`~sqlalchemy.types.TypeEngine` object
      which will provide result-set translation for this column.

    See :class:`.ColumnClause` for further examples.

    """
    return ColumnClause(text, type_=type_)