core.py 文件源码

def destroy(session, data, model_class=None, synchronize_session=False):
    """Delete bulk `data`.

    The `data` argument can be any of the following:

    - Single instance of `model_class`
    - List of `model_class` instances
    - Primary key value (single value or ``tuple`` of values for composite
      keys)
    - List of primary key values.
    - Dict containing primary key(s) mapping
    - List of dicts with primary key(s) mappings

    If a non-`model_class` instances are passed in, then `model_class` is
    required to know which table to delete from.

    Args:
        session (Session): SQLAlchemy session object.
        data (mixed): Data to delete from database.
        synchronize_session (bool|str): Argument passed to
            ``Query.delete``.

    Returns:
        int: Number of deleted records.
    """
    if not isinstance(data, list):
        data = [data]

    valid_model_class = isinstance(model_class, DeclarativeMeta)

    mapped_data = defaultdict(list)

    for idx, item in enumerate(data):
        item_class = type(item)

        if not isinstance(item_class, DeclarativeMeta) and valid_model_class:
            class_ = model_class
        else:
            class_ = item_class

        if not isinstance(class_, DeclarativeMeta):
            raise TypeError('Type of value given to destory() function is not '
                            'a valid SQLALchemy declarative class and/or '
                            'model class argument is not valid. '
                            'Item with index {0} and with value "{1}" is '
                            'an instance of "{2}" and model class is {3}.'
                            .format(idx, item, type(item), model_class))

        mapped_data[class_].append(item)

    delete_count = 0

    with transaction(session):
        for model_class, data in iteritems(mapped_data):
            count = (session.query(model_class)
                     .filter(primary_key_filter(data, model_class))
                     .options(orm.lazyload('*'))
                     .delete(synchronize_session=synchronize_session))
            delete_count += count

    return delete_count