我有两个Document,Picture,Seen_Picture
简单地
Class Picture
field :likes, type: Integer
field :is_new, type: Integer
end
和
Class SeenPicture
field :picture_id, type: String
field :is_new, type: Integer
field :user_id, type: String
end
我发现图片 is_new 字段为1而不是SeenPicture
离)
Picture(id, likes, is_new) :
[
[BSON::ObjectId('53f7fb5037646412e71b0000'), 2, 1],
[BSON::ObjectId('53f2aa8b6b6169e2eb010000'), 10, 1]
]
SeenPicture(id, picture_id, is_new, user_id) :
[
[BSON::ObjectId('53fbe7066b61694eb5000000'), '53f7fb5037646412e71b0000', 1, '53f2aa8b6b6169e2eb010000']
]
=> nonPicture是 BSON :: ObjectId(' 53f2aa8b6b6169e2eb010000')图片的最后一个文件
当我使用mysql
时(Picture.all.pluck(:id) - SeenPicture.all.pluck(:id)).sample(1).first
在mongodb中,如何找到nonSeen图片文档。