Question

我有一个集合：

//the json.
{
"ItemsToDelete" : [ 
        {
            "placeId" : "ChIJIQBpAG2ahYAR_6128GcTUEo",
            "users" : [ 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15")
            ]
        }, 
        {
            "placeId" : "ChIJIQBpAG2ahYAR_6128GcTUEo",
            "users" : [ 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15")
            ]
        }, 
        {
            "placeId" : "ChIJIQBpAG2ahYAR_6128GcTUEo",
            "users" : [ 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15")
            ]
        }
    ]
}  


{
"ItemsToRemove" : [ 
        {
            "ChIJIQBpAG2ahYAR_6128GcTUEo" : [ 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15")
            ]
        }, 
        {
            "ChIJIQBpAG2ahYAR_6128GcTUEo" : [ 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15")
            ]
        }, 
        {
            "ChIJIQBpAG2ahYAR_6128GcTUEo" : [ 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15"), 
                ObjectId("547e4650f3fb0a022110af15")
            ]
        }
    ]
}

然后我运行这个mongo shell查询从数组中拉出一个项目并删除：

db.users.update({"_id":ObjectId("54e664c4e7c3b4d3b5413e39")},{$pull:{ItemsToDelete : {placeId:"ChIJIQBpAG2ahYAR_6128GcTUE"}}},{ multi: true })

阵列保持不变。有没有想过为什么这不能拉动？

我试过了＆＃39; ItemsToDelete.placeId＆＃39;但是出错了：我在做“ItemsToDelete.placeId”时收到的错误=＆gt; '不能使用part（ItemsToDelete of ItemsToDelete.placeId）来遍历元素'

Answer 1

您查询并未提取任何项目，因为您在o值中缺少placeId。

> db.users.update(
    {"_id":ObjectId("54e664c4e7c3b4d3b5413e39")},
    {$pull:{ItemsToDelete : {placeId:"ChIJIQBpAG2ahYAR_6128GcTUE"}}},
                                                                ^
    { multi: true }
  )

应该是

> db.users.update(
    {"_id":ObjectId("54e664c4e7c3b4d3b5413e39")},
    {$pull:{ItemsToDelete : {placeId:"ChIJIQBpAG2ahYAR_6128GcTUEo"}}},
    { multi: true }
  )

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

> db.users.find().pretty()
{ "_id" : ObjectId("54eac8d51a0c74438c9dea10"), "ItemsToDelete" : [ ] }

$ pull mongodb不会删除物品

1 个答案: