MongoDB修改器的使用2

1."$inc"的使用

主要用来增加数值，比如网站的访问量，点击量，流量等

 db.games.insert({game:"pinball",user:"joe"})
 db.games.find()
 db.games.update({"game":"pinball","user":"joe"},{"$inc":{"score":}})
 db.games.update({"game":"pinball","user":"joe"},{"$inc":{"score":}})

运行结果分别为

 /* 1 */
 {
     "_id" : ObjectId("575a37da8fd26400d774e00a"),
     "game" : "pinball",
     "user" : "joe",
     "score" : 10150.0
 }

db.games.update({"game":"pinball","user":"joe"},{"$inc":{"score":50}})

 /* 1 */
 {
     "_id" : ObjectId("575a37da8fd26400d774e00a"),
     "game" : "pinball",
     "user" : "joe",
     "score" : 10200.0
 }