删除嵌套数组mongodb中的对象

如何解决删除嵌套数组mongodb中的对象

我有点像 mongo 中的下一个 json。

我的目标是用 "id_s": "1"

删除所有嵌套对象

{
  "_id": "5150a1199fac0e6910000002","name": "some name","p_a": [
    {
      "sub_name": "subname"
    },{
      "sub_name": "subname2","p_p": [
        {
          "last_level": "toDelete","id_s": "1"
        },{
          "last_level": "toKeep","id_s": "2"
        }
      ]
    },{
      "sub_name": "subname3","id_s": "2"
        }
      ]
    }
  ]
}

预期的 JSON：

{
  "_id": "5150a1199fac0e6910000002","p_p": [
        {
          "last_level": "toKeep","id_s": "2"
        }
      ]
    }
  ]
}

解决方法

这将为您提供 id_s: 2 位置的文档并忽略其余部分。

db.getCollection("test").aggregate(
[
    { 
        "$match" : { 
            "_id" : ObjectId("5150a1199fac0e6910000002")
        }
    },{ 
        "$unwind" : { 
            "path" : "$p_a"
        }
    },{ 
        "$unwind" : { 
            "path" : "$p_a.p_p"
        }
    },{ 
        "$match" : { 
            "p_a.p_p.id_s" : "2"
        }
    }
],{ 
    "allowDiskUse" : false
}

);

输出：

  /* 1 */
{
    "_id" : ObjectId("606d83fe44c9fc09f60d0756"),"name" : "some name","p_a" : {
        "sub_name" : "subname2","p_p" : {
            "last_level" : "toKeep","id_s" : "2"
        }
    }
}

/* 2 */
{
    "_id" : ObjectId("606d83fe44c9fc09f60d0756"),"p_a" : {
        "sub_name" : "subname3","id_s" : "2"
        }
    }
}