MongoDB - 涉及列表的upsert

Question

我是一个MongoDB新手,想问一下如何写一个涉及upsert和list的更新命令.

基本上我想完成这样的事情:

{"_id" : ObjectId("4c28f62cbf8544c60506f11d"),
"some_other_data":"goes here",
"trips": [
    {"name": "2010-05-10",
     "loc": [{"lat":21.321231, "lng": 16.8783234, "updated_at": "Mon May 10 2010 15:24:35"}, 
        {"lat":21.321231, "lng": 16.8783234, "updated_at": "Mon May 10 2010 15:24:24"}]
    },
    {"name": "2010-05-08",
     "loc": [{"lat":21.324239, "lng": 16.8735234, "updated_at": "Mon May 8 2010 11:18:05"},
        {"lat":21.311234, "lng": 16.8743271, "updated_at": "Mon May 8 2010 11:17:55"}, 
        {"lat":21.321238, "lng": 16.8782219, "updated_at": "Mon May 8 2010 11:17:45"}]
    }
]}

注意:

• 您提供旅行名称和当前位置
• 如果旅行不存在,则需要创建
• trips.name应该是唯一的,这样如果它存在,则追加到位置数组

这是我写的结合了位置运算符和$ push的查询.

    db.mycollection.update({"application_id": "MyTestApp", 
                            "trips.name": "2010-05-10"},
                           {$push: {'trips.$.loc': {"lat":11, "lng":11} }}, 
                           true);

但这会产生如下数据:

> db.mycollection.find({"application_id":"MyTestApp"})          
{ "_id" : ObjectId("4c29044ebf8544c60506f11f"), 
"application_id" : "MyTestApp", 
"trips" : { "$" : { "loc" : [ { "lat" : 11, "lng" : 11 } ] }, 
"name" : "2010-05-10" } 
}

你可以看到

• "旅行"不是一个阵列
• 字面上花了"$"并用它创造了一个关键(doh!)

到目前为止,我对MongoDB非常满意,但是编写复杂的查询肯定会有一个陡峭的学习曲线.

任何反馈将不胜感激.

提前谢谢,Amie

Answer 1

您不能混合使用位置运算符（“$”）和 upsert；在插入过程中，“$”将被视为字段名称。您不能对新文档执行此操作，只能对现有文档执行此操作。

我建议了一个更像这样的结构：

{"_id" : ObjectId("4c28f62cbf8544c60506f11d"),
"some_other_data":"goes here",
"trips": { 
    "2010-05-10":
       [{"lat":21.321231, "lng": 16.8783234, "updated_at": "Mon May 10 2010 15:24:35"}, 
        {"lat":21.321231, "lng": 16.8783234, "updated_at": "Mon May 10 2010 15:24:24"}],
    "2010-05-08": 
       [{"lat":21.324239, "lng": 16.8735234, "updated_at": "Mon May 8 2010 11:18:05"},
        {"lat":21.311234, "lng": 16.8743271, "updated_at": "Mon May 8 2010 11:17:55"}, 
        {"lat":21.321238, "lng": 16.8782219, "updated_at": "Mon May 8 2010 11:17:45"}]
    }
}

然后你可以像这样发布更新：

db.mycollection.update({application_id: "MyTestApp", "trips.2010-05-10":{$exists:true}},
                       {$push: {"trips.2010-05-10": {lat:11, lng:11} }}, 
                       true);

结果被插入。

> db.mycollection.find()
{ "_id" : ObjectId("4c2931d17b210000000045f0"), 
    "application_id" : "MyTestApp", 
    "trips" : { "2010-05-10" : [ { "lat" : 11, "lng" : 11 } ] } }

再次运行它会给你这个：

> db.mycollection.find()
{ "_id" : ObjectId("4c2932db7b210000000045f2"), 
    "application_id" : "MyTestApp", 
    "trips" : { "2010-05-10" : 
        [ { "lat" : 11, "lng" : 11 }, 
          { "lat" : 11, "lng" : 11 } ] } }