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MongoDB日常運維操作命令小結

必須 success fin sof rem nvi apr readwrite 狀態

總所周知,MongoDB是一個NoSQL非數據庫系統,即一個數據庫可以包含多個集合(Collection),每個集合對應於關系數據庫中的表;而每個集合中可以存儲一組由列標識的記錄,列是可以自由定義的,非常靈活,由一組列標識的實體的集合對應於關系數據庫表中的行。下面通過熟悉MongoDB的基本管理命令,來了解MongoDB提供的DBMS的基本功能和行為。

0)MongoDB的安裝

[root@centos6-vm01 ~]# curl -O https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-3.0.6.tgz
[root@centos6-vm01 ~]# tar -zxvf mongodb-linux-x86_64-3.0.6.tgz

[root@centos6-vm01 ~]# mv mongodb-linux-x86_64-3.0.6/ /usr/local/mongodb
[root@centos6-vm01 ~]# vim /etc/profile
......
export PATH=$PATH:/usr/local/mongodb/bin/
[root@centos6-vm01 ~]# source /etc/profile

啟動mongodb
[root@centos6-vm01 ~]# mkdir -p /data/db
[root@centos6-vm01 ~]# cd /usr/local/mongodb/bin/
[root@centos6-vm01 bin]# ./mongod &

[root@centos6-vm01 bin]# lsof -i:27017
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mongod 24304 root 5u IPv4 187360 0t0 TCP *:27017 (LISTEN)
mongod 24304 root 12u IPv4 187456 0t0 TCP localhost:27017->localhost:48742 (ESTABLISHED)
mongo 24319 root 3u IPv4 187455 0t0 TCP localhost:48742->localhost:27017 (ESTABLISHED)


連接mongodb報錯:
Failed global initialization: BadValue Invalid or no user locale set. Please ensure LANG and/or LC_* environment variables are set correctly.

解決辦法:
[root@centos6-vm01 ~]# vim /etc/profile
......
export LC_ALL=C
[root@centos6-vm01 ~]# source /etc/profile

1)MongoDB命令幫助系統
在安裝MongoDB後,啟動服務器進程(mongod),可以通過在客戶端命令mongo實現對MongoDB的管理和監控。看一下MongoDB的命令幫助系統:

[root@centos6-vm01 ~]# mongo
MongoDB shell version: 3.0.6
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:
2018-01-02T23:24:23.304+0000 I CONTROL [initandlisten] WARNING: You are running this process as the root user, which is not recommended.
2018-01-02T23:24:23.304+0000 I CONTROL [initandlisten]
2018-01-02T23:24:23.307+0000 I CONTROL [initandlisten]
2018-01-02T23:24:23.307+0000 I CONTROL [initandlisten]
WARNING: /sys/kernel/mm/transparent_hugepage/enabled is ‘always‘.
2018-01-02T23:24:23.307+0000 I CONTROL [initandlisten] We suggest setting it to ‘never‘
2018-01-02T23:24:23.307+0000 I CONTROL [initandlisten]
2018-01-02T23:24:23.307+0000 I CONTROL [initandlisten]
WARNING: /sys/kernel/mm/transparent_hugepage/defrag is ‘always‘.
2018-01-02T23:24:23.307+0000 I CONTROL [initandlisten] ** We suggest setting it to ‘never‘
2018-01-02T23:24:23.307+0000 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

這是MongoDB最頂層的命令列表,主要告訴我們管理數據庫相關的一些抽象的範疇:數據庫操作幫助、集合操作幫助、管理幫助。如果你想了解數據庫操作更詳細的幫助命令,可以直接使用db.help(),如下所示:

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
對數據庫進行管理和操作的基本命令,可以從上面獲取到。如果想要得到更多,而且每個命令的詳細用法,可以使用上面列出的db.listCommands()查詢。
另一個比較基礎的是對指定數據庫的集合進行操作、管理和監控,可以通過查詢db.mycoll.help()獲取到:

db.mycoll.help()
DBCollection help
db.mycoll.find().help() - show DBCursor help
db.mycoll.count()
db.mycoll.copyTo(newColl) - duplicates collection by copying all documents to newColl; no indexes are copied.
db.mycoll.convertToCapped(maxBytes) - calls {convertToCapped:‘mycoll‘, size:maxBytes}} command
db.mycoll.dataSize()
db.mycoll.distinct( key ) - e.g. db.mycoll.distinct( ‘x‘ )
db.mycoll.drop() drop the collection
db.mycoll.dropIndex(index) - e.g. db.mycoll.dropIndex( "indexName" ) or db.mycoll.dropIndex( { "indexKey" : 1 } )
db.mycoll.dropIndexes()
db.mycoll.ensureIndex(keypattern[,options])
db.mycoll.explain().help() - show explain help
db.mycoll.reIndex()
db.mycoll.find([query],[fields]) - query is an optional query filter. fields is optional set of fields to return.
e.g. db.mycoll.find( {x:77} , {name:1, x:1} )
db.mycoll.find(...).count()
db.mycoll.find(...).limit(n)
db.mycoll.find(...).skip(n)
db.mycoll.find(...).sort(...)
db.mycoll.findOne([query])
db.mycoll.findAndModify( { update : ... , remove : bool [, query: {}, sort: {}, ‘new‘: false] } )
db.mycoll.getDB() get DB object associated with collection
db.mycoll.getPlanCache() get query plan cache associated with collection
db.mycoll.getIndexes()
db.mycoll.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } )
db.mycoll.insert(obj)
db.mycoll.mapReduce( mapFunction , reduceFunction , <optional params> )
db.mycoll.aggregate( [pipeline], <optional params> ) - performs an aggregation on a collection; returns a cursor
db.mycoll.remove(query)
db.mycoll.renameCollection( newName , <dropTarget> ) renames the collection.
db.mycoll.runCommand( name , <options> ) runs a db command with the given name where the first param is the collection name
db.mycoll.save(obj)
db.mycoll.stats({scale: N, indexDetails: true/false, indexDetailsKey: <index key>, indexDetailsName: <index name>})
db.mycoll.storageSize() - includes free space allocated to this collection
db.mycoll.totalIndexSize() - size in bytes of all the indexes
db.mycoll.totalSize() - storage allocated for all data and indexes
db.mycoll.update(query, object[, upsert_bool, multi_bool]) - instead of two flags, you can pass an object with fields: upsert, multi
db.mycoll.validate( <full> ) - SLOW
db.mycoll.getShardVersion() - only for use with sharding
db.mycoll.getShardDistribution() - prints statistics about data distribution in the cluster
db.mycoll.getSplitKeysForChunks( <maxChunkSize> ) - calculates split points over all chunks and returns splitter function
db.mycoll.getWriteConcern() - returns the write concern used for any operations on this collection, inherited from server/db if set
db.mycoll.setWriteConcern( <write concern doc> ) - sets the write concern for writes to the collection
db.mycoll.unsetWriteConcern( <write concern doc> ) - unsets the write concern for writes to the collection
有關數據庫和集合管理的相關命令,是最基礎和最常用的,如集合查詢、索引操作等。下面通過實際的例子來演示一些常見的命令:

一、基本命令
1)show dbs
顯示當前數據庫服務器上的數據庫

2)use pagedb
切換到指定數據庫pagedb的上下文,可以在此上下文中管理pagedb數據庫以及其中的集合等

3)show collections
顯示數據庫中所有的集合(collection)

4)db.serverStatus()
查看數據庫服務器的狀態。
有時,通過查看數據庫服務器的狀態,可以判斷數據庫是否存在問題,如果有問題,如數據損壞,可以及時執行修復。

5)查詢指定數據庫統計信息
use fragment
db.stats()
查詢結果示例如下所示:

use fragment
switched to db fragment
db.stats()
{
"db" : "fragment",
"collections" : 0,
"objects" : 0,
"avgObjSize" : 0,
"dataSize" : 0,
"storageSize" : 0,
"numExtents" : 0,
"indexes" : 0,
"indexSize" : 0,
"fileSize" : 0,
"ok" : 1
}
6)查詢指定數據庫包含的集合名稱列表
db.getCollectionNames()
結果如下所示:

db.getCollectionNames()
[
"17u",
"baseSe",
"bytravel",
"daodao",
"go2eu",
"lotour",
"lvping",
"mafengwo",
"sina",
"sohu",
"system.indexes"
]
二、基本DDL和DML
1)創建數據庫
如果你習慣了關系型數據庫,你可能會尋找相關的創建數據庫的命令。在MongoDB中,你可以直接通過use dbname來切換到這個數據庫上下文下面,系統會自動延遲創建該數據庫,例如:

show dbs
local 0.078GB
use LuceneIndexDB
switched to db LuceneIndexDB
show dbs
local 0.078GB
db
LuceneIndexDB
db.storeCollection.save({‘version‘:‘3.5‘, ‘segment‘:‘e3ol6‘})
WriteResult({ "nInserted" : 1 })
show dbs
LuceneIndexDB 0.078GB
local 0.078GB

可見,在use指定數據庫後,並且向指定其中的一個集合並插入數據後,數據庫和集合都被創建了。

2)刪除數據庫
直接使用db.dropDatabase()即可刪除數據庫。

3)創建集合
可以使用命令db.createCollection(name, { size : ..., capped : ..., max : ... } )創建集合,示例如下所示:

db.createCollection(‘replicationColletion‘, {‘capped‘:true, ‘size‘:10240, ‘max‘:17855200})
{ "ok" : 1 }
show collections
replicationColletion
storeCollection
system.indexes
4)刪除集合
刪除集合,可以執行db.mycoll.drop()。

5)插入更新記錄
直接使用集合的save方法,如下所示:

db.storeCollection.save({‘version‘:‘3.5‘, ‘segment‘:‘e3ol6‘})
WriteResult({ "nInserted" : 1 })
更新記錄,使用save會將原來的記錄值進行覆蓋實現記錄更新。

6)查詢一條記錄
使用findOne()函數,參數為查詢條件,可選,系統會隨機查詢獲取到滿足條件的一條記錄(如果存在查詢結果數量大於等於1)示例如下所示:

db.storeCollection.findOne({‘version‘:‘3.5‘})
{
"_id" : ObjectId("5a4c1733f5c45f057ae82292"),
"version" : "3.5",
"segment" : "e3ol6"
}
7)查詢多條記錄
使用find()函數,參數指定查詢條件,不指定條件則查詢全部記錄。

8)刪除記錄
使用集合的remove()方法,參數指定為查詢條件,示例如下所示:

db.storeCollection.remove({‘version‘:‘3.5‘})
WriteResult({ "nRemoved" : 2 })
db.storeCollection.findOne()
null
9)創建索引
可以使用集合的ensureIndex(keypattern[,options])方法,示例如下所示:

use pagedb
switched to db pagedb
db.page.ensureIndex({‘title‘:1, ‘url‘:-1})
{
"createdCollectionAutomatically" : true,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
db.system.indexes.find()
{ "v" : 1, "key" : { "_id" : 1 }, "name" : "id", "ns" : "pagedb.page" }
{ "v" : 1, "key" : { "title" : 1, "url" : -1 }, "name" : "title_1url-1", "ns" : "pagedb.page" }
上述,ensureIndex方法參數中,數字1表示升序,-1表示降序。
使用db.system.indexes.find()可以查詢全部索引。

10)查詢索引
我們為集合建立的索引,那麽可以通過集合的getIndexes()方法實現查詢,示例如下所示:

db.page.getIndexes()
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"name" : "id",
"ns" : "pagedb.page"
},
{
"v" : 1,
"key" : {
"title" : 1,
"url" : -1
},
"name" : "title_1url-1",
"ns" : "pagedb.page"
}
]
當然,如果需要查詢系統中全部的索引,可以使用db.system.indexes.find()函數。

11)刪除索引
刪除索引給出了兩個方法:

db.mycoll.dropIndex(name)
2018-01-02T23:45:50.155+0000 E QUERY ReferenceError: name is not defined
at (shell):1:21
db.mycoll.dropIndexes()
{ "ok" : 0, "errmsg" : "ns not found" }

第一個通過指定索引名稱,第二個刪除指定集合的全部索引。

12)索引重建
可以通過集合的reIndex()方法進行索引的重建,示例如下所示:

db.page.reIndex()
{
"nIndexesWas" : 2,
"nIndexes" : 2,
"indexes" : [
{
"key" : {
"_id" : 1
},
"name" : "id",
"ns" : "pagedb.page"
},
{
"key" : {
"title" : 1,
"url" : -1
},
"name" : "title_1url-1",
"ns" : "pagedb.page"
}
],
"ok" : 1
}
13)統計集合記錄數

use fragment
switched to db fragment
db.baseSe.count()
36749

上述統計了數據庫fragment的baseSe集合中記錄數。

14)查詢並統計結果記錄數

use fragment
switched to db fragment
db.baseSe.find().count()
36749
find()可以提供查詢參數,然後查詢並統計結果。上述執行先根據查詢條件查詢結果,然後統計了查詢數據庫fragment的baseSe結果記錄集合中記錄數。

15)查詢指定數據庫的集合當前可用的存儲空間

use fragment
switched to db fragment
db.baseSe.storageSize()
142564096
16)查詢指定數據庫的集合分配的存儲空間

db.baseSe.totalSize()
144096000
上述查詢結果中,包括為集合(數據及其索引存儲)分配的存儲空間。

三、啟動與終止

1)正常啟動
[root@centos6-vm01 ~]# mongod --dbpath /data/db --logfile /var/mongo.log
說明:指定數據存儲目錄和日誌目錄

如果采用安全認證模式,需要加上--auth選項,如:
[root@centos6-vm01 ~]# mongod --auth --dbpath /data/db --logfile /var/mongo.log

2)以修復模式啟動
[root@centos6-vm01 ~]# mongod --repair
以修復模式啟動數據庫。

實際很可能數據庫數據損壞或數據狀態不一致,導致無法正常啟動MongoDB服務器,根據啟動信息可以看到需要進行修復。或者執行:
[root@centos6-vm01 ~]# mongod -f /etc/mongodb.conf --repair

3)終止服務器進程

db.shutdownServer()
終止數據庫服務器進程。或者,可以直接kill掉mongod進程即可。

四、安全管理

1)以安全認證模式啟動
[root@centos6-vm01 ~]# mongod --auth --dbpath /usr/mongo/data --logfile /var/mongo.log
使用--auth選項啟動mongod進程即可啟用認證模式。
或者,也可以修改/etc/mongodb.conf,設置auth=true,重啟mongod進程。

2)添加用戶

db.createUser({user: "admin",pwd: "1234!@#$qwer",roles: [ "readWrite", "dbAdmin" ]})
添加數據庫用戶,添加成功,則顯示結果如下所示:

1
2

db.createUser({user: "admin",pwd: "1234!@#$qwer",roles: [ "readWrite", "dbAdmin" ]})
Successfully added user: { "user" : "admin", "roles" : [ "readWrite", "dbAdmin" ] }
3)安全認證
前提是必須進入該用戶對應的database才行,出現1代表成功
db.auth("admin", "1234!@#$qwer")
數據庫安全認證。認證成功顯示結果:

use admin
switched to db admin
db.auth("admin", "1234!@#$qwer")

如果是認證用戶,執行某些命令,可以看到正確執行結果,如下所示:

db.system.users.find()
{ "_id" : "fragment.admin", "user" : "admin", "db" : "fragment", "credentials" : { "SCRAM-SHA-1" : { "iterationCount" : 10000, "salt" : "/QZtFAvcavqZIm15FmbToA==", "storedKey" : "t91XZuIrnUYtuN1bG+hNg58R+w0=", "serverKey" : "vZLGW0nVpGSKfUHsS2RABOXhOb4=" } }, "roles" : [ { "role" : "readWrite", "db" : "fragment" }, { "role" : "dbAdmin", "db" : "fragment" } ] }
4、為數據庫寫數據(同步到磁盤)加鎖
db.runCommand({fsync:1,lock:1})
說明:該操作已經對數據庫上鎖,不允許執行寫數據操作,一般在執行數據庫備份時有用。執行命令,結果示例如下:

db.runCommand({fsync:1,lock:1})
{
"info" : "now locked against writes, use db.fsyncUnlock() to unlock",
"seeAlso" : "http://dochub.mongodb.org/core/fsynccommand",
"ok" : 1
}
5)查看當前鎖狀態
db.currentOp()
說明:查詢結果如下所示:

db.currentOp()
{
"inprog" : [ ],
"fsyncLock" : true,
"info" : "use db.fsyncUnlock() to terminate the fsync write/snapshot lock"
}
其中,fsyncLock為1表示MongoDB的fsync進程(負責將寫入改變同步到磁盤)不允許其他進程執行寫數據操作

6)解鎖

use admin
db.$cmd.sys.unlock.findOne()
說明:執行解鎖,結果如下所示:

use admin
switched to db admin
db.$cmd.sys.unlock.findOne()
{ "ok" : 1, "info" : "unlock completed" }
可以執行命令查看鎖狀態:
db.currentOp()
狀態信息如下:

db.currentOp()
{ "inprog" : [ ] }
說明當前沒有鎖,可以執行寫數據操作。

五、據備份、恢復與遷移管理

1)備份全部數據庫
[root@centos6-vm01 ~]# mkdir testbak
[root@centos6-vm01 ~]# cd testbak
[root@centos6-vm01 ~]# mongodump
說明:默認備份目錄及數據文件格式為./dump/[databasename]/[collectionname].bson

2)備份指定數據庫
[root@centos6-vm01 ~]# mongodump -d pagedb
說明:備份數據庫pagedb中的數據。

3)備份一個數據庫中的某個集合
[root@centos6-vm01 ~]# mongodump -d pagedb -c page
說明:備份數據庫pagedb的page集合。

4)恢復全部數據庫
[root@centos6-vm01 ~]# cd testbak
[root@centos6-vm01 ~]# mongorestore --drop
說明:將備份的所有數據庫恢復到數據庫,--drop指定恢復數據之前刪除原來數據庫數據,否則會造成回復後的數據中數據重復。

5)恢復某個數據庫的數據
[root@centos6-vm01 ~]# cd testbak
[root@centos6-vm01 ~]# mongorestore -d pagedb --drop
說明:將備份的pagedb的數據恢復到數據庫。

6)恢復某個數據庫的某個集合的數據
[root@centos6-vm01 ~]# cd testbak
[root@centos6-vm01 ~]# mongorestore -d pagedb -c page --drop
說明:將備份的pagedb的的page集合的數據恢復到數據庫。

7)向MongoDB導入數據
[root@centos6-vm01 ~]# mongoimport -d pagedb -c page --type csv --headerline --drop < csvORtsvFile.csv
說明:將文件csvORtsvFile.csv的數據導入到pagedb數據庫的page集合中,使用cvs或tsv文件的列名作為集合的列名。

需要註意的是,使用--headerline選項時,只支持csv和tsv文件。
--type支持的類型有三個:csv、tsv、json
其他各個選項的使用,可以查看幫助:

[root@centos6-vm01 ~]# mongoimport --help
Usage:
mongoimport <options> <file>

Import CSV, TSV or JSON data into MongoDB. If no file is provided, mongoimport reads from stdin.

See http://docs.mongodb.org/manual/reference/program/mongoimport/ for more information.

general options:
--help print usage
--version print the tool version and exit

verbosity options:
-v, --verbose more detailed log output (include multiple times for more verbosity, e.g. -vvvvv)
--quiet hide all log output

connection options:
-h, --host= mongodb host to connect to (setname/host1,host2 for replica sets)
--port= server port (can also use --host hostname:port)

authentication options:
-u, --username= username for authentication
-p, --password= password for authentication
--authenticationDatabase= database that holds the user‘s credentials
--authenticationMechanism= authentication mechanism to use

namespace options:
-d, --db= database to use
-c, --collection= collection to use

input options:
-f, --fields= comma separated list of field names, e.g. -f name,age
--fieldFile= file with field names - 1 per line
--file= file to import from; if not specified, stdin is used
--headerline use first line in input source as the field list (CSV and TSV only)
--jsonArray treat input source as a JSON array
--type= input format to import: json, csv, or tsv (defaults to ‘json‘)

ingest options:
--drop drop collection before inserting documents
--ignoreBlanks ignore fields with empty values in CSV and TSV
--maintainInsertionOrder insert documents in the order of their appearance in the input source
-j, --numInsertionWorkers= number of insert operations to run concurrently (defaults to 1)
--stopOnError stop importing at first insert/upsert error
--upsert insert or update objects that already exist
--upsertFields= comma-separated fields for the query part of the upsert
--writeConcern= write concern options e.g. --writeConcern majority, --writeConcern ‘{w: 3, wtimeout: 500, fsync:
true, j: true}‘ (defaults to ‘majority‘)
8)從向MongoDB導出數據
[root@centos6-vm01 ~]# mongoexport -d pagedb -c page -q {} -f _id,title,url,spiderName,pubDate --csv > pages.csv

說明:將pagedb數據庫中page集合的數據導出到pages.csv文件,其中各選項含義:
-f 指定cvs列名為_id,title,url,spiderName,pubDate
-q 指定查詢條件
其他各個選項的使用,可以查看幫助:

[root@centos6-vm01 ~]# mongoexport --help
Usage:
mongoexport <options>

Export data from MongoDB in CSV or JSON format.

See http://docs.mongodb.org/manual/reference/program/mongoexport/ for more information.

general options:
--help print usage
--version print the tool version and exit

verbosity options:
-v, --verbose more detailed log output (include multiple times for more verbosity, e.g. -vvvvv)
--quiet hide all log output

connection options:
-h, --host= mongodb host to connect to (setname/host1,host2 for replica sets)
--port= server port (can also use --host hostname:port)

authentication options:
-u, --username= username for authentication
-p, --password= password for authentication
--authenticationDatabase= database that holds the user‘s credentials
--authenticationMechanism= authentication mechanism to use

namespace options:
-d, --db= database to use
-c, --collection= collection to use

output options:
-f, --fields= comma separated list of field names (required for exporting CSV) e.g. -f "name,age"
--fieldFile= file with field names - 1 per line
--type= the output format, either json or csv (defaults to ‘json‘)
-o, --out= output file; if not specified, stdout is used
--jsonArray output to a JSON array rather than one object per line
--pretty output JSON formatted to be human-readable

querying options:
-q, --query= query filter, as a JSON string, e.g., ‘{x:{$gt:1}}‘
-k, --slaveOk allow secondary reads if available (default true)
--forceTableScan force a table scan (do not use $snapshot)
--skip= number of documents to skip
--limit= limit the number of documents to export
--sort= sort order, as a JSON string, e.g. ‘{x:1}‘
註意:如果上面的選項-q指定一個查詢條件,需要使用單引號括起來,如下所示:

[root@centos6-vm01 ~]# mongoexport -d page -c Article -q ‘{"spiderName": "mafengwoSpider"}‘ -f _id,title,content,images,publishDate,spiderName,url --jsonArray > mafengwoArticle.txt
2018-01-03T08:12:41.234+0800 connected to: localhost
2018-01-03T08:12:41.234+0800 exported 0 records

[root@centos6-vm01 ~]# ll mafengwoArticle.txt
-rw-r--r--. 1 root root 3 Jan 3 00:12 mafengwoArticle.txt
否則,就會出現下面的錯誤:

1
ERROR: too many positional options
六、遠程連接管理

1)基於mongo實現遠程連接
[root@centos6-vm01 ~]# mongo 192.168.10.220:27017/pagedb
或者
[root@centos6-vm01 ~]# mongo 192.168.10.220:27017/pagedb -ukevin -p123456kevin

通過mongo實現連接,可以非常靈活的選擇參數選項,參看命令幫助,如下所示:

[root@centos6-vm01 ~]# mongo --help
MongoDB shell version: 3.0.6
usage: mongo [options] [db address] [file names (ending in .js)]
db address can be:
foo foo database on local machine
192.169.0.5/foo foo database on 192.168.0.5 machine
192.169.0.5:9999/foo foo database on 192.168.0.5 machine on port 9999
Options:
--shell run the shell after executing files
--nodb don‘t connect to mongod on startup - no
‘db address‘ arg expected
--norc will not run the ".mongorc.js" file on
start up
--quiet be less chatty
--port arg port to connect to
--host arg server to connect to
--eval arg evaluate javascript
-h [ --help ] show this usage information
--version show version information
--verbose increase verbosity
--ipv6 enable IPv6 support (disabled by default)

Authentication Options:
-u [ --username ] arg username for authentication
-p [ --password ] arg password for authentication
--authenticationDatabase arg user source (defaults to dbname)
--authenticationMechanism arg authentication mechanism
--gssapiServiceName arg (=mongodb) Service name to use when authenticating
using GSSAPI/Kerberos
--gssapiHostName arg Remote host name to use for purpose of
GSSAPI/Kerberos authentication

file names: a list of files to run. files have to end in .js and will exit after unless --shell is specified
2)基於MongoDB支持的javascript實現遠程連接
當你已經連接到一個遠程的MongoDB數據庫服務器(例如,通過mongo連接到192.168.0.184),現在想要在這個會話中連接另一個遠程的數據庫服務器(192.168.0.197),可以執行如下命令:

var x = new Mongo(‘192.168.10.220:27017‘)
var ydb = x.getDB(‘pagedb‘);
use ydb
switched to db ydb
db
ydb
ydb.page.findOne()
{
"_id" : ObjectId("4eded6a5bf3bfa0014000003"),
"content" : "巴黎是浪漫的城市,可是...",
"pubdate" : "2006-03-19",
"title" : "巴黎:從布魯塞爾趕到巴黎",
"url" : "http://france.bytravel.cn/Scenery/528/cblsegdbl.html"
}
上述通過MongoDB提供的JavaScript腳本,實現對另一個遠程數據庫服務器進行連接,操作指定數據庫pagedb的page集合。
如果啟用了安全認證模式,可以在獲取數據庫連接實例時,指定認證賬號,例如:

var x = new Mongo(‘192.168.0.197:27017‘)
var ydb = x.getDB(‘pagedb‘, ‘shirdrn‘, ‘(jkfFS$343$_\=\,.F@3‘);
use ydb
switched to db ydb

MongoDB日常運維操作命令小結