observation.py 文件源码

def total_size(self):
        "The total size (in bytes) of all Files associated with this session."
        from sqlalchemy import func
        from .file import File
        my_obsids = db.session.query(Observation.obsid).filter(Observation.session_id == self.id)
        return (db.session.query(func.sum(File.size))
                .filter(File.obsid.in_(my_obsids))
                .scalar())