Question

我正在尝试使用mgo（mongodb）创建一个简单的CRUD。

这是我的代码：

package main

import (
    "fmt"
    "time"

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

type State struct {
    CustomerId  string
    CreatedOn   time.Time
    CreatedBy   string
    Description string
}

type DataStore struct {
    session *mgo.Session
    err     error
}

func (ds *DataStore) getCol(collectionName string) *mgo.Collection {

    ds.session, ds.err = mgo.Dial("localhost:27017")

    if ds.err != nil {
        panic(ds.err)
    }

    return ds.session.DB("c3po_db").C(collectionName)
}

func (ds *DataStore) GetAll() []State {

    var states []State
    ds.err = ds.getCol("state").Find(bson.M{}).All(&states)
    if ds.err != nil {
        panic(ds.err)
    }

    ds.session.Close()
    return states
}

func (ds *DataStore) GetById(customerId string) State {

    var state State
    ds.err = ds.getCol("state").Find(bson.M{"customerId": customerId}).One(&state)
    if ds.err != nil {
        panic(ds.err)
    }

    ds.session.Close()
    return state

}

func (ds *DataStore) CreateOrUpdate(state State) bool {

    _, ds.err = ds.getCol("state").Upsert(
        bson.M{"customerId": state.CustomerId},
        bson.M{"$set": bson.M{"description": state.Description, "createdOn": state.CreatedOn, "createdBy": state.CreatedBy}})
    if ds.err != nil {
        panic(ds.err)
    } else {
        ds.session.Close()
        return true
    }

    ds.session.Close()
    return false
}

func main() {

    ds := DataStore{}

    state := State{CustomerId: "3", CreatedOn: time.Now(), CreatedBy: "Ivo", Description: "6"}

    ds.CreateOrUpdate(state)

    fmt.Println(ds.GetById("3"))

}

结果我得到了

{ 0001-01-01 00:00:00 +0000 UTC  0}

它为GetById打印一个空结果。 CreateOrUpdate方法部分工作。它只插入一条新记录，不会更新现有记录。这是正确的做法吗？如何使GetById和CreateOrUpdate方法有效？

Answer 1

以下代码按预期工作

package main

import (
    "fmt"
    "time"

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

type State struct {
    CustomerId  string
    CreatedOn   time.Time
    CreatedBy   string
    Description string
}

type DataStore struct {
    session *mgo.Session
    err     error
}

func (ds *DataStore) getCol(collectionName string) *mgo.Collection {

    ds.session, ds.err = mgo.Dial("localhost:27017")

    if ds.err != nil {
        panic(ds.err)
    }

    return ds.session.DB("c3po_db").C(collectionName)
}

func (ds *DataStore) GetAll() []State {

    var states []State
    ds.err = ds.getCol("state").Find(bson.M{}).All(&states)
    if ds.err != nil {
        panic(ds.err)
    }

    ds.session.Close()
    return states
}

func (ds *DataStore) GetById(customerId string) State {

    var state State
    ds.err = ds.getCol("state").Find(bson.M{"customerId": customerId}).One(&state)
    if ds.err != nil {
        panic(ds.err)
    }

    ds.session.Close()
    return state

}

func (ds *DataStore) CreateOrUpdate(state State) bool {

    _, ds.err = ds.getCol("state").Upsert(
        bson.M{"customerId": state.CustomerId},
        bson.M{"$set": state})
    if ds.err != nil {
        panic(ds.err)
    } else {
        ds.session.Close()
        return true
    }

    ds.session.Close()
    return false
}

func main() {

    ds := DataStore{}

    state := State{CustomerId: "3", CreatedOn: time.Now(), CreatedBy: "Ivo", Description: "6"}

    ds.CreateOrUpdate(state)

    fmt.Println(ds.GetById("3"))

    fmt.Println(ds.GetAll())

}

GetById和CreateOrUpdate不起作用

1 个答案: