我在mongodb数据库集合中有一些数据(我知道哪个集合，所以我只查看集合)，文档如下所示:{"_id":ObjectId("52a93577dadf672b96062729"),"owner":"user1","files":[{"IyzkmGh4YGD61Tc3TJjaEY17hDldH":"rws"}]}{"_id":ObjectId("52a92f43dadf672b96062725"),"owner":"user2","files":[{"tUI7RtvpHZklptvHVYssamlgHP6xs":"rws"},{"RsxRDQdXmHgmSLhMJ8tPxILxarruK