1、文档的多条插入

db.class.insertMany([{
  "name": "jack",
  "age": 18,
  "sex": 1,
  "hobby": [
    "画画",
    "唱歌"
  ]
},{
  "name": "kate",
  "age": 15,
  "sex": 0,
  "hobby": [
    "唱歌"
  ]
},{
  "name": "jom",
  "age": 25,
  "sex": 1,
  "hobby": [
    "画画"
  ]
},{
  "name": "lily",
  "age": 17,
  "sex": 0,
  "hobby": [
    "画画"
  ]
},{
  "name": "mark",
  "age": 18,
  "sex": 0,
  "hobby": [
    "画画"
  ]
},{
  "name": "frank",
  "age": 19,
  "sex": 0,
  "hobby": [
    "画画"
  ]
}])

2.查看年龄为18岁信息

3.查看年龄18-22岁信息

4.查看年龄17岁并喜欢画画的男生信息

5.查看年龄小于18岁或大于20岁的学生

6.找到班级中年龄最小的三位同学

class更新文档

1.将Kate兴趣爱好改为弹钢琴，足球

2.所有人年龄加一

 3.替换jom内容：年龄为25，备注：{{民族：“回族”，习俗：“不吃猪肉”}}