mongodb的curd

1. 创建一个学生信息表

use students

2.插入十五条数据

db.students.insertMany(
[
  {name:"bob", age:16,sex:"male",grade:95},
  {name:"ahn", age:18,sex:"female",grade:45},
  {name:"xi", age:15,sex:"male",grade:75},
  {name:"bob1", age:16,sex:"male",grade:95},
  {name:"ahn1", age:18,sex:"female",grade:45},
  {name:"xi1", age:15,sex:"male",grade:55},
  {name:"bob2", age:16,sex:"male",grade:95},
  {name:"ahn2", age:18,sex:"female",grade:60},
  {name:"xi2", age:15,sex:"male",grade:75},
  {name:"bob2", age:16,sex:"male",grade:95},
  {name:"ahn2", age:18,sex:"female",grade:45},
  {name:"xi2", age:15,sex:"male",grade:85},
  {name:"bob2", age:16,sex:"male",grade:95},
  {name:"ahn2", age:18,sex:"female",grade:45},
  {name:"xi2", age:15,sex:"male",grade:75},
]
)

3. 查询所有的男生数据（只需要学生的姓名和年龄）

db.students.find({sex:"male"},{name:1, age:true, _id:0})

4. 查询成绩几个的学生信息

db.students.find({grade:{"$gte":60}})

5. 查询所有16岁的男生和18岁的女生的数据

db.students.find({$or:[{sex:"male",age:16},{sex:"female",age:18}]})

6. 按照学生的年龄进行排序

db.students.find().sort({age:1})
db.students.find().sort({age:-1})

7. 将所有的学生年龄增加一岁

db.students.update({},{"$inc":{age:1}},{multi:true})

8. 将所有的女学生年龄增加一岁

db.students.update({sex:"female"},{"$inc":{age:1}},{multi:true})

9. 将所有的学生年龄增加一个address属性

db.students.update({},{"$set":{address:"--"}},{multi:true})