在MongoDB中按日期查询

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英文:

query by date in mongodb

问题

我能够使用golang驱动程序gopkg.in/mgo.vsgopkg.in/mgo.vs/bson将条目插入到MongoDB中,但我无法将其取出。在mongo shell中,如果我执行以下操作:

db.Items.find({ date : 1428762411980 })

它会显示我刚刚使用Go代码插入的条目。然而,如果我尝试在Go中执行以下操作来获取它,它告诉我找不到记录:

func fetch(w http.ResponseWriter, r *http.Request){
     var result SomeStruct
     date := r.FormValue("date")
     err := Items.Find(bson.M{"date":date}).One(&result)
     ...省略的代码...

}

func Items() *mgo.Collection {
   return DB().C("Items")
}

func DB() *mgo.Database {
  return DBSession().DB("mydb")
}

我注意到的一件事是,在shell中,日期存储为NumberLong

"date" : NumberLong("1428762411980")

我想知道在使用fetch函数中从表单接收到的日期值用于查询数据库之前,是否需要对其进行某些处理?

更新

在将数据保存到数据库之前,它以json字符串的形式出现,如下所示:

"date":1428762411980

然后我将其解码为一个结构体:

type blah struct{
    Id bson.ObjectId `json:"id" bson:"_id"`
    Date int64 `json:"date" bson:"date"`
}

并且它以以下方式保存(如shell中所示):

"date" : NumberLong("1428762411980")
英文:

I'm able to insert an entry into MongoDB using the golang driver gopkg.in/mgo.vs and gopkg.in/mgo.vs/bson but I'm not able to pull it out. In the mongo shell, if I do

db.Items.find({ date : 1428762411980 })

it shows me the entry that I just inserted with the Go code. However, if I try to do the following to fetch it in Go, it's telling me that the record isn't found

    func fetch(w http.ResponseWriter, r *http.Request){
         var result SomeStruct
         date := r.FormValue("date")
         err := Items.Find(bson.M{"date":date}).One(&result)
         ...code omitted...
    
    }

   func Items() *mgo.Collection {
       return DB().C("Items")
    }

   func DB() *mgo.Database {
      return DBSession().DB("mydb")
    }

One thing I noticed was that, in the shell, the date is stored as a NumberLong

 "date" : NumberLong("1428762411980")

I'm wondering if I have to do something with the date value that I receive from the form in the fetch function before using it to query the database?

Update

Before saving the data to the db, it comes in as a json string like this

"date":1428762411980

I then decode it into a struct

type blah struct{
	Id bson.ObjectId `json:"id" bson:"_id"`
	Date int64 `json:"date" bson: "date"`

And it gets saved like this (as shown in the shell)

 "date" : NumberLong("1428762411980")

答案1

得分: 1

r.FormValue 返回一个字符串,但你需要一个 int64 类型的值。可以使用 strconv.ParseInt 进行转换。然后你的查询应该可以工作了。

date, err := strconv.ParseInt(r.FormValue("date"), 10, 64)
// 处理错误
err = Items.Find(bson.M{"date": date}).One(&result)
英文:

r.FormValue returns a string, but you need an int64. Use strconv.ParseInt. Then your query should work.

date, err := strconv.ParseInt(r.FormValue("date"), 10, 64)
// handle err
err = Items.Find(bson.M{"date":date}).One(&result)

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  • 本文由 发表于 2015年4月11日 22:42:16
  • 转载请务必保留本文链接:https://go.coder-hub.com/29579123.html
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