Question

我正在尝试使用mgo更新文档数组中的对象。对象结构如下：

/* the lat/lng of the location you are trying to find places nearby */
$lat=56.25;
$lng=-2.65;

$sql="SELECT id, ( 3959 * acos( cos( radians( $lat ) ) * cos( radians( latitude ) ) * cos( radians( longitude ) - radians($lng) ) + sin( radians($lat) ) * sin( radians( latitude ) ) ) ) AS distance 
FROM markers 
HAVING distance < 25 
ORDER BY distance 
LIMIT 0,20;";

查询1： 我首先尝试更新{ "_id": 2, "status": 0, "details": [{ "id": 2, "category": "A", "obj": { "apple": 5, "banana": 2, "cherry": 10 }, "members": [{ "id": 3, "category": "A", "obj": { "apple": 5, "banana": 2, "cherry": 10 } }, { "id": 4, "category": "A", "obj": { "apple": 5, "banana": 2, "cherry": 10 } } ] }] }，尝试使用以下查询添加其他属性details > obj

"guava": 15

此查询既不会产生任何错误，也不会更新文档。任何人都可以告诉我怎样才能实现它

注意：我搜索了谷歌，但找不到我需要的内容。

QUERY2： 我还需要以cond := bson.M{ "$and": []bson.M{ bson.M{"document.details":bson.M{ "$elemMatch": bson.M{ "category": "A"} } }, bson.M{"document.status":0} } } query := bson.M{ "$set": bson.M{ "document.details.$.obj.guava":15 } } _, err := models.DbUpdateAll(Collection, cond, query)的方式更新details > members > obj。还请告诉我如何才能为details > obj实现相同的目标。

我花了好几个小时来搞清楚这一点，但没有成功。如果有人能指导我，我将感激不尽。

Answer 1

简单来说，我删除了成员。

package main

import (
    "fmt"
    "encoding/json"

    "gopkg.in/mgo.v2"
    "gopkg.in/mgo.v2/bson"
)

func main() {
    session, err := mgo.Dial("127.0.0.1")
    if err != nil {
       panic(err)
    }

    defer session.Close()

    // Optional. Switch the session to a monotonic behavior.
    session.SetMode(mgo.Monotonic, true)
    c := session.DB("test").C("mgo")

    cond := bson.M{"$and": []bson.M{bson.M{"details": bson.M{"$elemMatch": bson.M{"category": "A"}}}, bson.M{"status": 0}}}
    query := bson.M{"$set": bson.M{"details.$.obj.guava": 15}}

    res := []interface{}{}
    err = c.Find(cond).All(&res)

    if err != nil {
        fmt.Println("Before Update Read Error:", err)
        return
    }

    data, _ := json.MarshalIndent(res, "", " ")
    fmt.Printf("Before Update Read: %s\n", string(data))

    err = c.Update(cond, query)

    if err != nil {
        fmt.Println("Update Error:", err)
        return
    }

    fmt.Println("Update Succeed!")

    err = c.Find(cond).All(&res)
    if err != nil {
        fmt.Println("After Update Read Error:", err)
        return
    }

    data, _ = json.MarshalIndent(res, "", " ")
    fmt.Printf("After Update Read: %s\n", string(data))
}

结果：

Before Update Read: [
 {
  "_id": 2,
  "details": [
   {
    "category": "A",
    "id": 2,
    "obj": {
     "apple": 5,
     "banana": 2,
     "cherry": 10
    }
   }
  ],
  "status": 0
 }
]

Update Succeed!

After Update Read: [
 {
  "_id": 2,
  "details": [
   {
    "category": "A",
    "id": 2,
    "obj": {
     "apple": 5,
     "banana": 2,
     "cherry": 10,
     "guava": 15
    }
   }
  ],
  "status": 0
 }
]

为什么我的查询没有更新数组中的对象？

1 个答案: