Mongodb quickly get started with some simple operations of mongodb command line

stay MongoDB Inside , We usually use sets for the tables below the database collections To describe .

stay mongo Inside , Databases and tables can also be created without writing statements .

Common command usage is as follows ：

1

Show all the databases

  show dbs

2

Go to a database , Then perform some operations of creating tables

 use  Database name

If the database does not exist , Perform other operations later , For example, insert data into the table , The database will be created automatically

As can be seen from the above figure ： It doesn't exist study Database , But use use study database , And after inserting a piece of data into a table , It will automatically create tables and databases .

db.createCollection(" Table name ")

3

Display all tables under a database

 show tables /  show collections: Display all tables under the database

4

Insert data into the table

db. Collection name .insert( Document object );

db.user.insert({"age":30,"name":" Xiaobo "});

You can see from the above picture that ,insert() The method is actually not recommended , It is recommended to use insertOne, insertMany, perhaps bulkWrite Method .

Usage reference ：

db.user.insertOne({"age":30,"name":" Xiaobo 1"});
db.user.insertMany([{"age":30,"name":" Xiaobo 2"} ,{"age":30,"name":" Xiaobo 3  "}]);

The effect is as follows ：

bulkWrite The usage is complicated , I'll show you later .

5

Delete table

db. Collection name .drop()

6

Clear the data in the table

 db. Collection name .remove({})

7

Inquire about

db. Collection name .find({})

Queries have many complex uses , I will introduce it in detail later

8

Delete database

use db name

db.dropDatabase() ： Will delete the current database

That's all for this sharing , It is troublesome to add, delete, and modify the data in the query , Share later .