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What are the basic commands of mongodb? I believe that many inexperienced people are at a loss about this, so this article summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

1 switch database

Use admin

2 View the current database

Db

2.1 View all databases

Show dbs

3 View the tables under the current database

Show collections

4 Delete the database

Use test;db.dropDatabase (); # Delete the current database show dbs; # verify the deletion result

5 Delete a collection or table

Db.table_name.drop (); # Delete table table_name

6 View account information

Mongo-port=23000use admin;db.auth ('username','password') db.system.users.find (). Pretty () # View all account information show users; # View current account information db.getUser (' username') # View the information of the specified user

7 backup and restore using gzip compression. Just change the command, and the rest will remain the same. There is no need to set the user name and password here.

Mongodump-- port=23000-- archive=/data/mongo_backup/testdb-2.20191203.gz-- db testdb-2-- gzipmongorestore-- port=23000-- archive=/data/mongo_backup/testdb-2.20191203.gz-- db testdb-2-- gzip** this backup method generates a gzip file, which is also a file after decompression, and all the contents are put into one file.

8 backup without compression

Mongodump-- port=23000-- db=testdb-2-o / data/mongo_backup/20191203mongorestore-- port=23000-- db=testdb-2-- drop / data/mongo_backup/20191203/testdb-2** is backed up in this way, usually with two files per table: .bson and .metadata.json

9 use the mongo command to query in shell

# use eval mongo ip:port/database-- eval "[root@localhost ~] # mongo localhost:23000/testdb-2-- eval" printjson (db.table1.findOne ()) "MongoDB shell version v3.6.13connecting to: mongodb://localhost:23000/testdb-2?gssapiServiceName=mongodbImplicit session: session {" id ": UUID (" e87ef5ae-a6b7-47d6-a91c-65f3a0b81ac0 ")} MongoDB server version: 3.6.13 {" _ id ": ObjectId (" 5de60a767321940034390f16 ")," id ": 129 "name": "hehe"} # use-- quiet to remove unnecessary information [root@localhost ~] # mongo localhost:23000/testdb-2-- quiet-- eval "printjson (db.table2.findOne ())" {"_ id": ObjectId ("5de615b8eac07a724c6911b6"), "id": 6, "name": "hehe"} # Delete table [root@localhost ~] # mongo localhost:23000/testdb-2-- eval "db.table1.drop () "MongoDB shell version v3.6.13connecting to: mongodb://localhost:23000/testdb-2?gssapiServiceName=mongodbImplicit session: session {" id ": UUID (" 0cf5b11f-c6ef-417c-8bbd-a2f8414f589c ")} MongoDB server version: 3.6.13true

Use the mongo command in 10 shell scripts

#! / bin/bashmongo localhost:23000/testdb-2

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