1.1,简介
MongoDB 是由 C++语言编写一个基于分布式文件存储的开源 NoSQL 数据库系统。在高负 载的情况下，可添加更多的节点，以保证服务性能。在许多场景下用于代替传统的关系型 数据库或键/值存储方式。旨在为 Web 应用提供可扩展的高性能数据存储解决方案。
MongoDB 提供了一个面向文档存储，操作起来比较简单和容易，可以存储比较复杂的 数据类型。最大的特点是支持的查询语言非常强大，语法优点类似于面向对象的查询语 言。几乎可以实现类似关系数据库单表查询的绝大部分功能，而且还支持对数据建立索 引。是一个面向集合的，模式自由的文档型数据库。
1.2,MongoDB 适用领域：
l 网站数据
l 分布式场景
l 缓存层
l 文档格式存储
1.3,逻辑结构
（1）文档（document）：是 mongodb 的核心概念，是 mongodb 逻辑存储的最小单元
（2）集合（collection）：多个文档组成集合
（3）数据库（database）：多个集合组成数据库
1.4,物理存储结构
1.4.1,数据存储结构
l 命名空间文件（ns）
l 数据文件（0,1,2）
1.4.2,日志存储结构
l 系统日志文件 logpath
l journal 日志文件
l oplog 复制操作日志文件
l 慢查询日志
1.5,数据类型
BSON 是 Binary JSON，是二进制的格式，能将 mongdb 的所有文档表示为字节字符串。
JSON 是一种轻量级的数据交换格式。它基于 JavaScript 的一个子集
1.5.1,BSON 的数据类型
l null，代表空或者不存在
l布尔，只有 true 和 false
l 数字，64 位浮点数
l 字符串，utf8 字符串
l 数组，值或者列表可表示为数组
l 对象，对象的数据
1.5.2,BSON 的特点
简单，简洁，容易理解、解析、记忆
1.5.3,命名规则
l 文档的键命名几乎所有 utf8 字符，只有少数例外：$开头； （空字符）；_下划线开头。
l 集合的命名几乎所有 utf8 字符，只有少数例外：$开头； （空字符）；system.开头；”” 空字符串。
l 数据库的命名几乎所有 utf8 字符，只有少数例外：””空字符串； ；空格；. 点； ；
/。
二，安装搭建mongodb
1．安装mongodb
1.1,环境：
CentOS-6.8 192.168.25.32/24 MongoDB
1.2下载此次安装版本
[root@MongodDB tmp]# wget https://www.mongodb.com/dr/fastdl.mongodb.org/linux/mongodb-linux-x86_64-rhel62- 3.2.7.tgz/download
1.3,解压安装包，并移动到/usr/local/下
[root@MongodDB tmp]# tar zxvf mongodb-linux-x86_64-rhel62-3.2.7.tgz
[root@MongodDB tmp]# mv mongodb-linux-x86_64-rhel62-3.2.7/ /usr/local/mongodb
1.4指定同一时间最多可开启的文件数
[root@MongodDB ~]# ulimit -n
1024
[root@MongodDB ~]# ulimit -n 65535
[root@MongodDB ~]# ulimit -n
65535
1.5,用户最多可开启的程序数目
[root@MongodDB ~]# ulimit -u
31994
[root@MongodDB ~]# ulimit -u 65535
[root@MongodDB ~]# ulimit -u
65535
1.6,创建数据目录和日志文件及目录，并创建相应配置文件
[root@MongodDB ~]# mkdir -p /data/mongodb1
[root@MongodDB ~]# mkdir -p /data/logs/mongodb
[root@MongodDB ~]# touch /data/logs/mongodb/mongodb1.log
[root@MongodDB ~]# cd /usr/local/mongodb/
[root@MongodDB mongodb]# ls
bin GNU-AGPL-3.0 MPL-2 README THIRD-PARTY-NOTICES
[root@MongodDB mongodb]# mkdir conf
[root@MongodDB mongodb]# cat conf/mongodb1.conf
port=27017
dbpath=/data/mongodb1
logpath=/data/logs/mongodb/mongodb1.log
logappend=true
fork=true
maxConns=5000
storageEngine=mmapv1
1.7,启动MongoDB数据库,-f 指定配置文件
[root@MongodDB mongodb]# /usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/mongodb1.conf
[root@MongodDB mongodb]# /usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/mongodb1.conf
about to fork child process, waiting until server is ready for connections.
forked process: 2016
child process started successfully, parent exiting
[root@MongodDB mongodb]# netstat -anpt | grep mongod
tcp 0 0 0.0.0.0:27017 0.0.0.0:* LISTEN 2016/mongod
[root@MongodDB mongodb]# ps aux | grep mongdb
root 2044 0.0 0.0 103324 892 pts/0 S+ 20:04 0:00 grep mongdb
1.8,设置开机自动启动
[root@MongodDB mongodb]# cat /etc/rc.local
#!/bin/sh
#
# This script will be executed *after* all the other init scripts.
# You can put your own initialization stuff in here if you don't
# want to do the full Sys V style init stuff.
touch /var/lock/subsys/local
rm -f /data/mongodb1/mongod.lock
/usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/mongodb1.conf
1.9,连接数据库
[root@MongodDB mongodb]# /usr/local/mongodb/bin/mongo
MongoDB shell version: 3.2.7
connecting to: test
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
• http://docs.mongodb.org/
Questions? Try the support group
• http://groups.google.com/group/mongodb-user
Server has startup warnings:
2019-09-02T19:50:12.394+0800 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2019-09-02T19:50:12.394+0800 I CONTROL [initandlisten]
2019-09-02T19:50:12.395+0800 I CONTROL [initandlisten]
2019-09-02T19:50:12.395+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2019-09-02T19:50:12.395+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2019-09-02T19:50:12.395+0800 I CONTROL [initandlisten]
2019-09-02T19:50:12.395+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2019-09-02T19:50:12.395+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2019-09-02T19:50:12.395+0800 I CONTROL [initandlisten]
> show dbs
local 0.078GB
> exit
Bye
1.10,去除启动时的报错
[root@MongodDB mongodb]# echo never > /sys/kernel/mm/transparent_hugepage/enabled
[root@MongodDB mongodb]# echo never > /sys/kernel/mm/transparent_hugepage/defrag
[root@MongodDB mongodb]# vim .bash_profile
[root@MongodDB mongodb]# cat .bash_profile
alias mongo=/usr/local/mongodb/bin/mongo
[root@MongodDB mongodb]# source .bash_profile
1.11,关闭服务的三种方法
方法一：
[root@MongodDB ~]# mongo
> use admin
switched to db admin
> db.shutdownServer();
server should be down...
2019-09-02T20:19:49.361+0800 I NETWORK [thread1] trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2019-09-02T20:19:49.361+0800 W NETWORK [thread1] Failed to connect to 127.0.0.1:27017, reason: errno:111 Connection refused
2019-09-02T20:19:49.361+0800 I NETWORK [thread1] reconnect 127.0.0.1:27017 (127.0.0.1) failed failed
> exit
bye
[root@MongodDB ~]# netstat -anpt |grep mongod
方法二：
[root@MongodDB ~]# /usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/mongodb1.conf
about to fork child process, waiting until server is ready for connections.
forked process: 2081
child process started successfully, parent exiting
[root@MongodDB ~]# netstat -anpt | grep mongod
tcp 0 0 0.0.0.0:27017 0.0.0.0:* LISTEN 2081/mongod
[root@MongodDB ~]# /usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/mongodb1.conf --shutdown
killing process with pid: 2081
[root@MongodDB ~]# netstat -anpt | grep mongod
方法三：
[root@MongodDB ~]# /usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/mongodb1.conf
about to fork child process, waiting until server is ready for connections.
forked process: 2102
child process started successfully, parent exiting
[root@MongodDB ~]# ps -ef |grep mongod
root 2102 1 0 20:22 ? 00:00:00 /usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/mongodb1.conf
root 2118 1857 0 20:22 pts/0 00:00:00 grep mongod
[root@MongodDB ~]# kill 2102
[root@MongodDB ~]# netstat -anpt | grep mongod
[root@MongodDB ~]#
1.12,开启两个实例：
[root@MongodDB ~]# cd /usr/local/mongodb/conf/
[root@MongodDB conf]# ls
mongodb1.conf
[root@MongodDB conf]# cp mongodb{1,2}.conf
[root@MongodDB conf]# ls
mongodb1.conf mongodb2.conf
[root@MongodDB conf]# cat mongodb2.conf
port=27018
dbpath=/data/mongodb2
logpath=/data/logs/mongodb/mongodb2.log
logappend=true
fork=true
maxConns=5000
storageEngine=mmapv1
[root@MongodDB conf]# mkdir /data/mongodb2
[root@MongodDB conf]# touch /data/logs/mongodb/mongodb2.log
[root@MongodDB conf]# chmod 777 /data/logs/mongodb/mongodb2.log
1.13,编写启停脚本
[root@MongodDB conf]# cd /etc/init.d/
[root@MongodDB init.d]# cat mongodb
#!/bin/bash
INSTANCE=$1
ACTION=$2
case "$ACTION" in
'start')
/usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/"$INSTANCE".conf;;
'stop')
/usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/"$INSTANCE".conf --shutdown;;
'restart')
/usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/"$INSTANCE".conf --shutdown
/usr/local/mongodb/bin/mongod -f /usr/local/mongodb/conf/"$INSTANCE".conf;;
esac
[root@MongodDB init.d]# chmod +x mongodb
[root@MongodDB init.d]# /etc/init.d/mongodb mongodb1 start
about to fork child process, waiting until server is ready for connections.
forked process: 2139
child process started successfully, parent exiting
[root@MongodDB init.d]# /etc/init.d/mongodb mongodb2 start
about to fork child process, waiting until server is ready for connections.
forked process: 2155
child process started successfully, parent exiting
[root@MongodDB init.d]# netstat -anpt |grep mongod
tcp 0 0 0.0.0.0:27017 0.0.0.0:* LISTEN 2139/mongod
tcp 0 0 0.0.0.0:27018 0.0.0.0:* LISTEN 2155/mongod
到此mongodb已经搭建完毕了
2,基本操作
| 操作 | 作用 |
|---|---|
| show dbs | 查看当前示例下的数据库列表，等同于 show database |
| show users | 显示用户 |
| use <db_name> | 切换当前数据库 |
| db.help() | 显示数据库操作命令 |
| show collections | 显示当前数据库中的集合，等同于 show tables |
| db.mycoll.help() | 显示集合操作命令，mycoll 是当前下叫做 mycoll 的集合 |
| db.foo.find() | 对当前数据库中 foo 集合进行数据查找 |
[root@MongodDB ~]# mongo
> show dbs
local 0.078GB
> show databases
local 0.078GB
> use benet
switched to db benet
> show dbs
local 0.078GB
> show tables
> use local
switched to db local
> show tables
startup_log
system.indexes
> use benet
switched to db benet
> db.user.insert({"id":1,"name":"Tom"});
WriteResult({ "nInserted" : 1 })
> show dbs
benet 0.078GB
local 0.078GB
> show collections
system.indexes
user
> db.user.find()
{ "_id" : ObjectId("5d6d0d5bea5345188da4699e"), "id" : 1, "name" : "Tom" }
>
bye
查看帮助
[root@MongodDB ~]# /usr/local/mongodb/bin/mongod --help
[root@MongodDB ~]# mongo
MongoDB shell version: 3.2.7
connecting to: test
Server has startup warnings:
2019-09-02T20:31:36.534+0800 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2019-09-02T20:31:36.534+0800 I CONTROL [initandlisten]
> help
• db.help() help on db methods
• db.mycoll.help() help on collection methods
• sh.help() sharding helpers
• rs.help() replica set helpers
• help admin administrative help
• help connect connecting to a db help
• help keys key shortcuts
• help misc misc things to know
• help mr mapreduce
• show dbs show database names
• show collections show collections in current database
• show users show users in current database
• show profile show most recent system.profile entries with time >= 1ms
• show logs show the accessible logger names
• show log [name] prints out the last segment of log in memory, 'global' is default
• use <db_name> set current database
• db.foo.find() list objects in collection foo
• db.foo.find( { a : 1 } ) list objects in foo where a == 1
• it result of the last line evaluated; use to further iterate
• DBQuery.shellBatchSize = x set default number of items to display on shell
• exit quit the mongo shell
>
> db.help()
DB methods:
• db.adminCommand(nameOrDocument) - switches to 'admin' db, and runs command [ just calls db.runCommand(...) ]
• db.auth(username, password)
• db.cloneDatabase(fromhost)
• db.commandHelp(name) returns the help for the command
• db.copyDatabase(fromdb, todb, fromhost)
• db.createCollection(name, { size : ..., capped : ..., max : ... } )
• db.createUser(userDocument)
• db.currentOp() displays currently executing operations in the db
• db.dropDatabase()
• db.eval() - deprecated
• db.fsyncLock() flush data to disk and lock server for backups
• db.fsyncUnlock() unlocks server following a db.fsyncLock()
• db.getCollection(cname) same as db['cname'] or db.cname
• db.getCollectionInfos([filter]) - returns a list that contains the names and options of the db's collections
• db.getCollectionNames()
• db.getLastError() - just returns the err msg string
• db.getLastErrorObj() - return full status object
• db.getLogComponents()
• db.getMongo() get the server connection object
• db.getMongo().setSlaveOk() allow queries on a replication slave server