How does mongodb realize the creation and deletion of databases, the creation of deletion tables, and the addition, deletion, modification and query of data

MongoDB How to create and delete a database 、 Create delete table 、 Data addition, deletion, modification and query

This article mainly introduces “MongoDB How to create and delete a database 、 Create delete table 、 Data addition, deletion, modification and query ”, In daily operation , I believe a lot of people are MongoDB How to create and delete a database 、 Create delete table 、 There are doubts about data addition, deletion, modification and query , Xiao Bian consulted all kinds of materials , Sort out simple and easy-to-use operation methods , I hope to answer ”MongoDB How to create and delete a database 、 Create delete table 、 Data addition, deletion, modification and query ” Your doubts help ！ Next , Please follow Xiaobian to learn ！

One 、 Database usage

Turn on mongodb service ： To manage the database , You have to turn on the service first , Turn on service usage  

mongod --dbpath  c:\mongodb

management mongodb database ：( Must be in the new cmd Input in )

mongo

Clear the screen ：

cls

Check all databases list

show dbs

Two 、 Create database

Using a database 、 Create database

use student

If you really want to create this database successfully , Then a data must be inserted .
You can't insert data directly into the database , You can only go to the assembly (collections) Insert data . There is no need to create a collection specifically , only
If you need to write some syntax to insert data, you will create a collection ：

Insert a piece of data

db.student.insert({“name”:”xiaoming”});

db.student System discovery student It's a strange collection name , So the collection is automatically created .
Displays the current data set （mysql Chinese called Watch ）

show collections

Delete database , Delete the current database

db.dropDatabase();

Delete the collection , Delete the specified collection Delete table
Delete the collection

db.COLLECTION_NAME.drop()db.user.drop()

3、 ... and 、 Insert （ increase ） data

insert data , With the insertion of data , The database was created successfully , The collection was also created successfully .

db.  Table name .insert({"name":"zhangsan"}); student  Collection name （ surface ）

Four 、 Find data

1 、 Check all records

db.userInfo.find();

amount to ：select* from userInfo;
2 、 Query the duplicate data of a column in the removed current aggregation set

db.userInfo.distinct("name");

It will filter out name The same data in
amount to ：select distict name from userInfo;
3 、 Inquire about age = 22 The record of

db.userInfo.find({"age": 22});

amount to ： select * from userInfo where age = 22;
4 、 Inquire about age > 22 The record of

db.userInfo.find({age: {$gt: 22}});

amount to ：select * from userInfo where age >22;
5 、 Inquire about age < 22 The record of

db.userInfo.find({age: {$lt: 22}});

amount to ：select * from userInfo where age <22;
6 、 Inquire about age >= 25 The record of

db.userInfo.find({age: {$gte: 25}});

amount to ：select * from userInfo where age >= 25;
7 、 Inquire about age <= 25 The record of

db.userInfo.find({age: {$lte: 25}});

8 、 Inquire about age >= 23 also age <= 26 Pay attention to the writing style

db.userInfo.find({age: {$gte: 23, $lte: 26}});

9 、 Inquire about name Contained in the mongo The data of Fuzzy queries are used to search

db.userInfo.find({name: /mongo/});

amount to ：%%
select * from userInfo where name like ‘%mongo%’;
10 、 Inquire about name China and Israel mongo At the beginning

db.userInfo.find({name: /^mongo/});

amount to ：select * from userInfo where name like ‘mongo%’;

11 、 Query specified column name 、age data

db.userInfo.find({}, {name: 1, age: 1});

amount to ：select name, age from userInfo;
Of course name It can also be used. true or false, When used ture In the case of the river name:1 The effect is the same , If you use false It's to exclude name, Show name Column information other than .
12 、 Query specified column name 、age data , age > 25

db.userInfo.find({age: {$gt: 25}}, {name: 1, age: 1});

amount to ：select name, age from userInfo where age >25;
13 、 Sort by age 1 Ascending -1 Descending

 Ascending ：db.userInfo.find().sort({age: 1}); Descending ：db.userInfo.find().sort({age: -1});

14 、 Inquire about name = zhangsan, age = 22 The data of

db.userInfo.find({name: 'zhangsan', age: 22});

amount to ：select * from userInfo where name = ‘zhangsan’ and age = ‘22’;
15 、 Before query 5 Data

db.userInfo.find().limit(5);

amount to ：selecttop 5 * from userInfo;
16 、 Inquire about 10 Data after

db.userInfo.find().skip(10);

amount to ：select * from userInfo where id not in ( select top 10 * from userInfo );

5、 ... and 、 Delete data

db.collectionsNames.remove( { "borough": "Manhattan" } )db.users.remove({age: 132});By default, the remove() method removes all documents that match the remove condition. Usethe justOne option to limit the remove operation to only one of the matching documents.db.restaurants.remove( { "borough": "Queens" }, { justOne: true }

Here we are , About “MongoDB How to create and delete a database 、 Create delete table 、 Data addition, deletion, modification and query ” That's the end of my study , I hope we can solve your doubts . The combination of theory and practice can better help you learn , Let's try ！ If you want to continue to learn more related knowledge , Please continue to pay attention to Yisu cloud website , Xiaobian will continue to strive to bring you more practical articles ！