sqla_compat.py 文件源码

def _is_type_bound(constraint):
    # this deals with SQLAlchemy #3260, don't copy CHECK constraints
    # that will be generated by the type.
    if sqla_100:
        # new feature added for #3260
        return constraint._type_bound
    else:
        # old way, look at what we know Boolean/Enum to use
        return (
            constraint._create_rule is not None and
            isinstance(
                getattr(constraint._create_rule, "target", None),
                sqltypes.SchemaType)
        )