linux-MongoDB service

MongoDB is a nosql database. It has the characteristics of high performance and schema-less document type. It has the richest functions among nosql databases and is most similar to a relational database. The database format is BSON.

Related concepts

Example: The MongoDB process running on the system is similar to the mysql instance

Library: Each database is independent, has its own users, permissions, and independent storage collections, similar to the mysql library

Collection: consists of a set of documents, similar to a mysql table

Document: The minimum data set of the mongodb database is a data unit composed of multiple key-value pairs in an orderly manner, similar to the data records of mysql

Primary key: uniquely identifies a row of data

characteristic

Facial collection document storage, suitable for storing data in json form

The format is free, the data format is not fixed, and changes in the data structure will not affect program operation.

Object-oriented SQL query statements basically cover all query statements in relational databases

With index support, query efficiency is faster

Supports replication and failover

Sharded clusters can be used to improve query performance

Application scenarios

game

logistics

social contact

Internet of things

Live video

Big Data

2. Installation

1. Compile and install

2. rpm installation

Configure mongo source vim /etc/yum.repo.d/mongo.repo

    [mongodb-org-4.2]
        name=MongoDb Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/4.2/x86_64/
        gpgcheck=1
        enabled=1
        gpgkey=https://www.monyum install -y mongodb-orggodb.org/static/gpg/server-4.2.asc

Install yum install -y mongodb-org

Start the database systemctl start mongod.service

2. Directory structure

rpm -ql mongodb-org-server

                /etc/mongod.conf main configuration file
                                                       port: 27017 listening port number
                                                       bindIp: 127.0.0.1 listening address

/run/mongodb PID file

/usr/bin/mongod startup command

/var/lib/mongo stores data files

/var/log/mongodb log

rpm -ql mongodb-org-shell

/usr/bin/mongo client commands

rpm -ql mongodb-org-tools

/usr/bin/mongodump backup database

/usr/bin/mongoexport backup document

/usr/bin/mongoimport restore documentation

/usr/bin/mongorestore restore database

3. Default database

admin

From a permissions perspective, this is the "root" database. If a user is added to this database, the user automatically inherits all database permissions.
Certain server-side commands can also only be run from this database, such as listing all databases or shutting down the server.

local

This database is never replicated and can be used to store any collection limited to a single local server.

config

When Mongo is used for sharding setup, the config database is used internally to save information about shards.

4. Database operations

library operations

show database show database

show dbs

Display the current database db

Switch database use dbName

Database creation: Implicit creation
does not require active creation. Use use newDB to automatically create a non-existing database. It
will only be saved after the collection is created in the library and viewed using show dbs.

To delete data, use dbName db.dropdatabase() (it needs to be in the library to delete it)

Document operations

View the collection show tables

Create a collection db.createCollection("test ") (collection test)

Delete collection db. The name of the collection to be deleted.drop()

Insert data (document) db.collection name.insert({key:value}) insert data in a single row

db.setname.insertmany ( [ {key:value},{key:value},{key:value} ] )

Insert data into multiple rows

The default data type of mongodb numbers is float. To change it to integer type: NumberInt (number)

Query data db.set name.find({}) full set query

db.collection name.find() full collection query

Conditional query db.info.find({query condition 1key:value,query condition 2,...},{key1:1|0,key2:1|0,...})

key:1 is displayed, key:0 is not displayed

When there is only one key displayed, key:1 only displays the key and the corresponding value, and key:0 displays all other keyvalues except this key.

Query how many documents there are in the collection db.collection name.count()

Delete data db.Collection name.remove({})

db.Collection name.remove({key:value})

Update data db.info.update({_id:"3"}, {$set:{name:"jack"}})

All documents that meet the conditions are updated db.info.update({'name':'wangwu'},{$set:{password:"tom"}},{multi:true})

Update the document to increment the value db.info.update({userid:""},{$inc:{likenum:NumberInt()}})

5. MongoDB database backup

1. Backup

mongo dump

        -h=hostname:port
        -u=<username>
        -p=<password>
        --authenticationDatabase=<dbname>
        -d=<database>
        -o=<path>

语法 mongodump -d dbName -h hostName:port -u userName -p Password -o backupDirectory

mongoexport

        -h=hostname:port
        -u=<username>
        -p=<password>
        --authenticationDatabase=<dbname>
        -d=<database>
        -o=<path>

语法 mongoexport -d dbName -c tableName -h hostName:port -u userName -p Password -o backupDirectory/jsonFile.json

2. Recovery

mongorestore

        -h=hostname:port
        -u=<username>
        -p=<password>
        --authenticationDatabase=<dbname>
        -d=<database>
        --drop When a collection with the same name exists in the target database, delete and restore it

语法 mongorestore -h hostName -u username -p password -d dbName -c tableName bakcupDirector/bsonFile

mongoimport

·-h=hostname:port
        -u=<username>
        -p=<password>
        --authenticationDatabase=<dbname>
        -d=<database>
        --drop When a collection with the same name exists in the target database, delete and restore it

语法 mongoimport -d dbName -c tableName -h hostName:port -u userName -p Password backupDirectory/jsonFile.json