详解Golang使用MongoDB通用操作

type LikeBest struct {
 AuthorName string `bson:"authorname,omitempty"`
 BookName  string `bson:"bookname,omitempty"`
 PublishTime string `bson:"publishtime,omitempty"`
 LastReadTime string `bson:"lastreadtime,omitempty"`
}

type Personnal struct {
 UserName  string  `bson:"username,omitempty"`
 WhereCity  string  `bson:"wherecity,omitempty"`
 BookSCount int  `bson:"bookscount,omitempty"`
 FavoriteBooks []LikeBest `bson:"favoratebooks,omitempty"`
}

 session, err := mgo.Dial("localhost:27017")
 if err != nil {
  panic(err)
 }
 defer session.Close()

 c := session.DB("PersonManage").C("Persons")

err := c.Insert(&p) //p为插入的结构体数据

change := mgo.Change{
  Update: bson.M{"$set": p},
  ReturnNew: false,
  Remove: false,
  Upsert: true,
}
_, err := c.Find(bson.M{"username": "impressionw"}).Apply(change, nil)

err = c.Find(bson.M{"username": "impressionw"}).One(&result)

select{‘filedname':0}，表示忽略该字段则结果不返回此字段
select{‘filedname':1}，表示关注该字段则只返回关注字段
err = c.Find(bson.M{"username": "impressionw"}).Select(bson.M{"favoratebooks": 1}).One(&result)

var result interface{}
err = c.Find(bson.M{"username": "impressionw"}).Select(bson.M{"_id": 1}).One(&result)

var document_id string
switch value := result.(type) {
case bson.M:
 mapid := value["_id"]
 if mapid != nil {
  id := mapid.(bson.ObjectId)
  document_id = id.Hex()
 }
}

query = bson.M{"username": bson.M{"$regex": "impressionw"}}

pipe := c.Pipe([]bson.M{{"$unwind": "$favoratebooks"},
  {"$match": bson.M{"username": "impressionw", "favoratebooks.bookname": "The Go Programming Language"}},
  {"$project": bson.M{"favoratebooks": 1}}})
resp := []bson.M{}
err := pipe.All(&resp)

err = c.Update(bson.M
{"username": "impressionw"
}, 
bson.M{"$set": bson.M
{"wherecity": "ShangHai"
}})

change := mgo.Change{
  Update: bson.M{"$set": bson.M{"favoratebooks.$.lastreadtime": "Oct 26, 2017"}},
  ReturnNew: false,
  Remove: false,
  Upsert: true,
 }
query := bson.M{"username": "impressionw", "favoratebooks": bson.M{"$elemMatch": bson.M{"bookname": "The Go Programming Language"}}}
_, err = c.Find(query).Select(bson.M{"favoratebooks.bookname": 1}).Apply(change, nil)

Act := []LikeBest{
 LikeBest{
  AuthorName: "YuHen",
  BookName:  "Go Learning",
  PublishTime: "Dec 27, 2014",
  LastReadTime: "Dec 29, 2016",
 },
}
change := mgo.Change{
 Update: bson.M{"$inc": bson.M{"bookscount": 1}, "$push": bson.M{"favoratebooks": bson.M{"$each": Act}}},
 ReturnNew: false,
 Remove: false,
 Upsert: true,
}
_, err := c.Find(bson.M{"username": "impressionw"}).Apply(change, nil)

var option = bson.M
{"$pull": bson.M{"favoratebooks": bson.M{"bookname": "Go Learning"}}, 
"$inc": bson.M{"bookscount": -1}}
err := c.Update(bson.M{"username": "impressionw"}, option)

var data = bson.M{"$unset": bson.M
{"favoratebooks": true},
 "$set": bson.M{"bookscount": 0}}
err = c.Update(bson.M
{"username": "impressionw"}, data)

err := session.DB("PersonManage").C("Persons").Remove(bson.M
{"_id":bson.ObjectIdHex("