每篇半小时1天入门MongoDB——2.MongoDB环境变量配置和Shell操作

前言：为什么不是1天精通？大家都是成年人、明白人、聪明人，就不要像忽悠小孩子一样啦.......入门容易精通难，入门可能1天，精通则可能十年磨一剑才略有所成......

配置环境变量

Win10系统为例

右键单击“此电脑”——属性——高级系统设置——高级——环境变量，添加C:\Program Files\MongoDB\Server\3.0\bin;。注意：要以;隔开各种变量。

这样的话就可以直接在CMD命令窗口中输入mongo

表示环境变量设置成功，并已经连接到默认数据库test中。

我们可以输入mongod --help来查看相关的帮助信息

C:\Users\zouqi>mongod --help
Options:
 
General options:
  -h [ --help ]               show this usage information
  --version                   show version information
  -f [ --config ] arg         configuration file specifying additional options
  -v [ --verbose ] [=arg(=v)] be more verbose (include multiple times for more
                              verbosity e.g. -vvvvv)
  --quiet                     quieter output
  --port arg                  specify port number - 27017 by default
  --bind_ip arg               comma separated list of ip addresses to listen on
                              - all local ips by default
  --ipv6                      enable IPv6 support (disabled by default)
  --maxConns arg              max number of simultaneous connections - 1000000
                              by default
  --logpath arg               log file to send write to instead of stdout - has
                              to be a file, not directory
  --logappend                 append to logpath instead of over-writing
  --logRotate arg             set the log rotation behavior (rename|reopen)
  --timeStampFormat arg       Desired format for timestamps in log messages.
                              One of ctime, iso8601-utc or iso8601-local
  --pidfilepath arg           full path to pidfile (if not set, no pidfile is
                              created)
  --keyFile arg               private key for cluster authentication
  --setParameter arg          Set a configurable parameter
  --httpinterface             enable http interface
  --clusterAuthMode arg       Authentication mode used for cluster
                              authentication. Alternatives are
                              (keyFile|sendKeyFile|sendX509|x509)
  --auth                      run with security
  --noauth                    run without security
  --jsonp                     allow JSONP access via http (has security
                              implications)
  --rest                      turn on simple rest api
  --slowms arg (=100)         value of slow for profile and console log
  --profile arg               0=off 1=slow, 2=all
  --cpu                       periodically show cpu and iowait utilization
  --sysinfo                   print some diagnostic system information
  --noIndexBuildRetry         don't retry any index builds that were
                              interrupted by shutdown
  --noscripting               disable scripting engine
  --notablescan               do not allow table scans
 
Windows Service Control Manager options:
  --install                install Windows service
  --remove                 remove Windows service
  --reinstall              reinstall Windows service (equivalent to --remove
                           followed by --install)
  --serviceName arg        Windows service name
  --serviceDisplayName arg Windows service display name
  --serviceDescription arg Windows service description
  --serviceUser arg        account for service execution
  --servicePassword arg    password used to authenticate serviceUser
 
Replication options:
  --oplogSize arg       size to use (in MB) for replication op log. default is
                        5% of disk space (i.e. large is good)
 
Master/slave options (old; use replica sets instead):
  --master              master mode
  --slave               slave mode
  --source arg          when slave: specify master as <server:port>
  --only arg            when slave: specify a single database to replicate
  --slavedelay arg      specify delay (in seconds) to be used when applying
                        master ops to slave
  --autoresync          automatically resync if slave data is stale
 
Replica set options:
  --replSet arg           arg is <setname>[/<optionalseedhostlist>]
  --replIndexPrefetch arg specify index prefetching behavior (if secondary)
                          [none|_id_only|all]
 
Sharding options:
  --configsvr           declare this is a config db of a cluster; default port
                        27019; default dir /data/configdb
  --shardsvr            declare this is a shard db of a cluster; default port
 
SSL options:
  --sslOnNormalPorts                    use ssl on configured ports
  --sslMode arg                         set the SSL operation mode
                                        (disabled|allowSSL|preferSSL|requireSSL
                                        )
  --sslPEMKeyFile arg                   PEM file for ssl
  --sslPEMKeyPassword arg               PEM file password
  --sslClusterFile arg                  Key file for internal SSL
                                        authentication
  --sslClusterPassword arg              Internal authentication key file
                                        password
  --sslCAFile arg                       Certificate Authority file for SSL
  --sslCRLFile arg                      Certificate Revocation List file for
                                        SSL
  --sslDisabledProtocols arg            Comma separated list of TLS protocols
                                        to disable [TLS1_0,TLS1_1,TLS1_2]
  --sslWeakCertificateValidation        allow client to connect without
                                        presenting a certificate
  --sslAllowConnectionsWithoutCertificates
                                        allow client to connect without
                                        presenting a certificate
  --sslAllowInvalidHostnames            Allow server certificates to provide
                                        non-matching hostnames
  --sslAllowInvalidCertificates         allow connections to servers with
                                        invalid certificates
  --sslFIPSMode                         activate FIPS 140-2 mode at startup
 
Storage options:
  --storageEngine arg (=mmapv1) what storage engine to use
  --dbpath arg                  directory for datafiles - defaults to \data\db\
                                which is C:\data\db\ based on the current
                                working drive
  --directoryperdb              each database will be stored in a separate
                                directory
  --noprealloc                  disable data file preallocation - will often
                                hurt performance
  --nssize arg (=16)            .ns file size (in MB) for new databases
  --quota                       limits each database to a certain number of
                                files (8 default)
  --quotaFiles arg              number of files allowed per db, implies --quota
  --smallfiles                  use a smaller default file size
  --syncdelay arg (=60)         seconds between disk syncs (0=never, but not
                                recommended)
  --upgrade                     upgrade db if needed
  --repair                      run repair on all dbs
  --repairpath arg              root directory for repair files - defaults to
                                dbpath
  --journal                     enable journaling
  --nojournal                   disable journaling (journaling is on by default
                                for 64 bit)
  --journalOptions arg          journal diagnostic options
  --journalCommitInterval arg   how often to group/batch commit (ms)
 
WiredTiger options:
  --wiredTigerCacheSizeGB arg           maximum amount of memory to allocate
                                        for cache; defaults to 1/2 of physical
                                        RAM
  --wiredTigerStatisticsLogDelaySecs arg (=0)
                                        seconds to wait between each write to a
                                        statistics file in the dbpath; 0 means
                                        do not log statistics
  --wiredTigerJournalCompressor arg (=snappy)
                                        use a compressor for log records
                                        [none|snappy|zlib]
  --wiredTigerDirectoryForIndexes       Put indexes and data in different
                                        directories
  --wiredTigerCollectionBlockCompressor arg (=snappy)
                                        block compression algorithm for
                                        collection data [none|snappy|zlib]
  --wiredTigerIndexPrefixCompression arg (=1)
                                        use prefix compression on row-store
                                        leaf pages

如果你不喜欢看英文可以网上搜中文帮助介绍。

mongoDB和关系型数据库的对比

关系数据的表的record必须保证拥有每一个field
mongoDBde meiyige documentde key可以不一样
关系型数据库查询使用SQL
mongoDB查询使用内置find函数——》基于BSON的特殊查询工具

Shell操作

创建一个数据库——use[databaseName]

这时数据库并没有被正在创建，而是处于mongodb的一个预处理缓存池当中，如果你什么也不干就离开的花这个空数据库就会被删除。
查看所有数据库——show dbs
```
> show dbs
demo        0.078GB
local       0.078GB
myDatabase  0.078GB
>
```
这个时候我们看到myTest这个数据库是还没有创建的。

给指定数据库添加集合并且添加记录 ——db.[documentName].insert({...})

> db.persons.insert({name:'yujie'})
WriteResult({ "nInserted" : 1 })
>

执行上面语句后才真正创建数据库。

> show dbs
demo        0.078GB
local       0.078GB
myDatabase  0.078GB
myTest      0.078GB
>

查看数据库中的所有文档——show collections
```
> show collections
persons
system.indexes
>
```
我们看到多了一个system.indexes文档，这是系统自动创建的一个索引文档，当插入记录的时候，自动创建了一个字段_id，并在这个字段上面创建了索引。我们来查看下索引：
```
> db.system.indexes.find()
{ "v" : 1, "key" : { "_id" : 1 }, "name" : "_id_", "ns" : "myTest.persons" }
>
```

查看指定文档的数据——db.[documentName].find()&db.[documentName].findOne()

在这之前，我们再来往persons文档中插入一条记录

> db.persons.insert({name:'楚留香'})
WriteResult({ "nInserted" : 1 })
>

查找persons文档中的所有记录

> db.persons.find()
{ "_id" : ObjectId("593959250ab68d9cc7011a93"), "name" : "yujie" }
{ "_id" : ObjectId("59395c350ab68d9cc7011a94"), "name" : "楚留香" }
>

查找persons文档中的第一条记录

> db.persons.findOne()
{ "_id" : ObjectId("593959250ab68d9cc7011a93"), "name" : "yujie" }
>

更新文档数据——db.[documentName].update({查询条件},{更新内容})

这里我们用到了一个update方法，我们来看下它的几个参数分别代表什么

参数1：查询的条件

参数2：更新的字段

参数3：如果不存在则插入

参数4：是否允许修改多条记录

更新name为yujie的记录
```
> db.persons.update({name:'yujie'},{$set:{name:'玉杰'}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
```
查看更新后的记录：
```
> db.persons.find()
{ "_id" : ObjectId("593959250ab68d9cc7011a93"), "name" : "玉杰" }
{ "_id" : ObjectId("59395c350ab68d9cc7011a94"), "name" : "楚留香" }
```

删除文档中的数据——db.[documentName].remove({...})

插入一条测试记录

> db.persons.insert({name:'test'})
WriteResult({ "nInserted" : 1 })

插入后：

> db.persons.find()
{ "_id" : ObjectId("593959250ab68d9cc7011a93"), "name" : "玉杰" }
{ "_id" : ObjectId("59395c350ab68d9cc7011a94"), "name" : "楚留香" }
{ "_id" : ObjectId("593961530ab68d9cc7011a95"), "name" : "test" }
>

删除文档中的数据

> db.persons.remove({name:'test'})
WriteResult({ "nRemoved" : 1 })
>

删除后结果：

> db.persons.find()
{ "_id" : ObjectId("593959250ab68d9cc7011a93"), "name" : "玉杰" }
{ "_id" : ObjectId("59395c350ab68d9cc7011a94"), "name" : "楚留香" }
>

删除数据库——db.dropDatabase()

查看所有数据库

> show dbs
demo        0.078GB
foobar      0.078GB
local       0.078GB
myDatabase  0.078GB
myTest      0.078GB
>

假设我要删除foobar数据库，先使用use foobar切换到foobar数据库，然后执行 db.dropDatabase()，执行结果如下：

> db.dropDatabase()
{ "dropped" : "foobar", "ok" : 1 }
>

再次查看所有数据库：

> show dbs
demo        0.078GB
local       0.078GB
myDatabase  0.078GB
myTest      0.078GB
>

Shell的help

里面有所有的shell可以完成的命令帮助，全局的help数据库相关的db.help()，集合相关的db.[documentName].help()

db.help()

> 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()
        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
        db.getName()
        db.getPrevError()
        db.getProfilingLevel() - deprecated
        db.getProfilingStatus() - returns if profiling is on and slow threshold
        db.getReplicationInfo()
        db.getSiblingDB(name) get the db at the same server as this one
        db.getWriteConcern() - returns the write concern used for any operations on this db, inherited from server object if set
        db.hostInfo() get details about the server's host
        db.isMaster() check replica primary status
        db.killOp(opid) kills the current operation in the db
        db.listCommands() lists all the db commands
        db.loadServerScripts() loads all the scripts in db.system.js
        db.logout()
        db.printCollectionStats()
        db.printReplicationInfo()
        db.printShardingStatus()
        db.printSlaveReplicationInfo()
        db.dropUser(username)
        db.repairDatabase()
        db.resetError()
        db.runCommand(cmdObj) run a database command.  if cmdObj is a string, turns it into { cmdObj : 1 }
        db.serverStatus()
        db.setLogLevel(level,<component>)
        db.setProfilingLevel(level,<slowms>) 0=off 1=slow 2=all
        db.setWriteConcern( <write concern doc> ) - sets the write concern for writes to the db
        db.unsetWriteConcern( <write concern doc> ) - unsets the write concern for writes to the db
        db.setVerboseShell(flag) display extra information in shell output
        db.shutdownServer()
        db.stats()
        db.version() current version of the server
>

db.persons.help()

> db.persons.help()
DBCollection help
        db.persons.find().help() - show DBCursor help
        db.persons.count()
        db.persons.copyTo(newColl) - duplicates collection by copying all documents to newColl; no indexes are copied.
        db.persons.convertToCapped(maxBytes) - calls {convertToCapped:'persons', size:maxBytes}} command
        db.persons.dataSize()
        db.persons.distinct( key ) - e.g. db.persons.distinct( 'x' )
        db.persons.drop() drop the collection
        db.persons.dropIndex(index) - e.g. db.persons.dropIndex( "indexName" ) or db.persons.dropIndex( { "indexKey" : 1 } )
        db.persons.dropIndexes()
        db.persons.ensureIndex(keypattern[,options])
        db.persons.explain().help() - show explain help
        db.persons.reIndex()
        db.persons.find([query],[fields]) - query is an optional query filter. fields is optional set of fields to return.
                                                      e.g. db.persons.find( {x:77} , {name:1, x:1} )
        db.persons.find(...).count()
        db.persons.find(...).limit(n)
        db.persons.find(...).skip(n)
        db.persons.find(...).sort(...)
        db.persons.findOne([query])
        db.persons.findAndModify( { update : ... , remove : bool [, query: {}, sort: {}, 'new': false] } )
        db.persons.getDB() get DB object associated with collection
        db.persons.getPlanCache() get query plan cache associated with collection
        db.persons.getIndexes()
        db.persons.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } )
        db.persons.insert(obj)
        db.persons.mapReduce( mapFunction , reduceFunction , <optional params> )
        db.persons.aggregate( [pipeline], <optional params> ) - performs an aggregation on a collection; returns a cursor
        db.persons.remove(query)
        db.persons.renameCollection( newName , <dropTarget> ) renames the collection.
        db.persons.runCommand( name , <options> ) runs a db command with the given name where the first param is the collection name
        db.persons.save(obj)
        db.persons.stats({scale: N, indexDetails: true/false, indexDetailsKey: <index key>, indexDetailsName: <index name>})
        db.persons.storageSize() - includes free space allocated to this collection
        db.persons.totalIndexSize() - size in bytes of all the indexes
        db.persons.totalSize() - storage allocated for all data and indexes
        db.persons.update(query, object[, upsert_bool, multi_bool]) - instead of two flags, you can pass an object with fields: upsert, multi
        db.persons.validate( <full> ) - SLOW
        db.persons.getShardVersion() - only for use with sharding
        db.persons.getShardDistribution() - prints statistics about data distribution in the cluster
        db.persons.getSplitKeysForChunks( <maxChunkSize> ) - calculates split points over all chunks and returns splitter function
        db.persons.getWriteConcern() - returns the write concern used for any operations on this collection, inherited from server/db if set
        db.persons.setWriteConcern( <write concern doc> ) - sets the write concern for writes to the collection
        db.persons.unsetWriteConcern( <write concern doc> ) - unsets the write concern for writes to the collection
>

mongoDB的API

http://api.mongodb.com/js/
数据库和集合命名规范

不能是空字符串
不得含有' '（空格）、,、$、/，\、和\O（空字符）；
应全部小写
最多64个字节
数据库名不能与现有系统保留库同名，如admin，local，及config

数据库i命名为db-text这样的集合也是合法的，但是不能通过db.[documentName]得到了，要改为db.getCollection("documentName")，因为db-text会被当成是减。

mongoDB的shell内置javascript引擎可以直接执行js代码

function insert(object){
db.getCollection("db-text").insert(object)
}
insert({age:29})

shell可以用eval

> db.eval("return 'mongodb'")
WARNING: db.eval is deprecated
mongodb
>

BSON是JSON的扩展，他新增了诸如日期，浮点等JSON不支持的数据类型

MongoDB语法与现有关系型数据库SQL语法比较

MongoDB语法                <==>                   MySql语法
db.test.find({'name':'foobar'}) <==> select * from test where name='foobar'
db.test.find()                  <==> select * from test
db.test.find({'ID':10}).count() <==> select count(*) from test where ID=10
db.test.find().skip(10).limit(20)     <==> select * from test limit 10,20
db.test.find({'ID':{$in:[25,35,45]}}) <==> select * from test where ID in (25,35,45)
db.test.find().sort({'ID':-1})        <==> select * from test order by ID desc
db.test.distinct('name',{'ID':{$lt:20}})  <==> select distinct(name) from test where ID<20
db.test.group({key:{'name':true},cond:{'name':'foo'},reduce:function(obj,prev){prev.msum+=obj.marks;},initial:{msum:0}})  <==> select name,sum(marks) from test group by name
db.test.find('this.ID<20',{name:1})  <==> select name from test where ID<20
db.test.insert({'name':'foobar','age':25})<==>insert into test ('name','age') values('foobar',25)
db.test.remove({})                <==> delete * from test
db.test.remove({'age':20})        <==> delete test where age=20
db.test.remove({'age':{$lt:20}})  <==> elete test where age<20
db.test.remove({'age':{$lte:20}}) <==> delete test where age<=20
db.test.remove({'age':{$gt:20}})  <==> delete test where age>20
db.test.remove({'age':{$gte:20}}) <==> delete test where age>=20
db.test.remove({'age':{$ne:20}})  <==> delete test where age!=20
db.test.update({'name':'foobar'},{$set:{'age':36}}) <==> update test set age=36 where name='foobar'
db.test.update({'name':'foobar'},{$inc:{'age':3}})  <==> update test set age=age+3 where name='foobar'

注意以上命令大小写敏感。