mongodb的增删改插的一个实例

Posted 2020-10-07 追梦的独行者

创建一个学生信息表（至少包含：姓名，性别，成绩，年龄）

1、写入十五条不同的数据

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: "male", grade: 45},
{ name: "xi1", age: 15, sex: "female", grade: 55},
{ name: "bob2", age: 16, sex: "female", grade: 95},
{ name: "ahn2", age: 18, sex: "male", grade: 60},
{ name: "xi2", age: 15, sex: "male", grade: 75},
{ name: "bob3", age: 16, sex: "male", grade: 95},
{ name: "ahn3", age: 18, sex: "female", grade: 45},
{ name: "xi3", age: 15, sex: "male", grade: 85},
{ name: "bob4", age: 16, sex: "female", grade: 95},
{ name: "ahn4", age: 18, sex: "male", grade: 45},
{ name: "xi4", age: 15, sex: "male", grade: 75}
]
)
2、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})

3、查询成绩及格的学生信息（学生成绩大于或等于60分）

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

4、查询所有18岁的男生和16岁的女生的数据

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

5、按照学生的年龄进行排序

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

6、将所有的女学生年龄增加一岁

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