MongoDB的所有请求都以命令的形式发出，支持的命令列表参考Database Commands
The mongo Shell：
https://docs.mongodb.com/manual/mongo/
db是mongoDB的全局变量，持有当前数据库schema的引用。
首次进入客户端shell，敲入命令db
> db
test
看看当前数据库server的状态
> db.serverStatus()
{
"host" : "jacks-MacBook-Air.local",
"advisoryHostFQDNs" : [
"jacks-macbook-air.local"
],
"version" : "3.2.4",
"process" : "mongod",
"pid" : NumberLong(68),
"uptime" : 616301,
"uptimeMillis" : NumberLong(616300555),
"uptimeEstimate" : 35411,
"localTime" : ISODate("2017-03-20T05:42:48.260Z"),
"asserts" : {
"regular" : 0,
"warning" : 0,
"msg" : 0,
"user" : 0,
"rollovers" : 0
},
"connections" : {
"current" : 2,
"available" : 3274,
"totalCreated" : NumberLong(6)
},
"extra_info" : {
"note" : "fields vary by platform",
"page_faults" : 4993
},
"globalLock" : {
"totalTime" : NumberLong("616300534000"),
"currentQueue" : {
"total" : 0,
"readers" : 0,
"writers" : 0
},
"activeClients" : {
"total" : 9,
"readers" : 0,
"writers" : 0
}
},
"locks" : {
"Global" : {
"acquireCount" : {
"r" : NumberLong(1471174),
"w" : NumberLong(2920),
"W" : NumberLong(4)
}
},
"Database" : {
"acquireCount" : {
"r" : NumberLong(734121),
"w" : NumberLong(2901),
"R" : NumberLong(4),
"W" : NumberLong(19)
}
},
"Collection" : {
"acquireCount" : {
"r" : NumberLong(774729),
"w" : NumberLong(2901)
}
},
"Metadata" : {
"acquireCount" : {
"w" : NumberLong(1)
}
}
},
"network" : {
"bytesIn" : NumberLong(1529),
"bytesOut" : NumberLong(6719),
"numRequests" : NumberLong(21)
},
"opcounters" : {
"insert" : 0,
"query" : 1,
"update" : 0,
"delete" : 0,
"getmore" : 0,
"command" : 22
},
"opcountersRepl" : {
"insert" : 0,
"query" : 0,
"update" : 0,
"delete" : 0,
"getmore" : 0,
"command" : 0
},
"storageEngine" : {
"name" : "wiredTiger",
"supportsCommittedReads" : true
},
"wiredTiger" : {
"uri" : "statistics:",
"LSM" : {
"sleep for LSM checkpoint throttle" : 0,
"sleep for LSM merge throttle" : 0,
"rows merged in an LSM tree" : 0,
"application work units currently queued" : 0,
"merge work units currently queued" : 0,
"tree queue hit maximum" : 0,
"switch work units currently queued" : 0,
"tree maintenance operations scheduled" : 0,
"tree maintenance operations discarded" : 0,
"tree maintenance operations executed" : 0
},
"async" : {
"number of allocation state races" : 0,
"number of operation slots viewed for allocation" : 0,
"current work queue length" : 0,
"number of flush calls" : 0,
"number of times operation allocation failed" : 0,
"maximum work queue length" : 0,
"number of times worker found no work" : 0,
"total allocations" : 0,
"total compact calls" : 0,
"total insert calls" : 0,
"total remove calls" : 0,
"total search calls" : 0,
"total update calls" : 0
},
"block-manager" : {
"mapped bytes read" : 0,
"bytes read" : 446464,
"bytes written" : 163840,
"mapped blocks read" : 0,
"blocks pre-loaded" : 25,
"blocks read" : 86,
"blocks written" : 25
},
"cache" : {
"tracked dirty bytes in the cache" : 0,
"tracked bytes belonging to internal pages in the cache" : 21407,
"bytes currently in the cache" : 237704,
"tracked bytes belonging to leaf pages in the cache" : 216297,
"maximum bytes configured" : 4294967296,
"tracked bytes belonging to overflow pages in the cache" : 0,
"bytes read into cache" : 174182,
"bytes written from cache" : 110151,
"pages evicted by application threads" : 0,
"checkpoint blocked page eviction" : 0,
"unmodified pages evicted" : 0,
"page split during eviction deepened the tree" : 0,
"modified pages evicted" : 0,
"pages selected for eviction unable to be evicted" : 0,
"pages evicted because they exceeded the in-memory maximum" : 0,
"pages evicted because they had chains of deleted items" : 0,
"failed eviction of pages that exceeded the in-memory maximum" : 0,
"hazard pointer blocked page eviction" : 0,
"internal pages evicted" : 0,
"maximum page size at eviction" : 0,
"eviction server candidate queue empty when topping up" : 0,
"eviction server candidate queue not empty when topping up" : 0,
"eviction server evicting pages" : 0,
"eviction server populating queue, but not evicting pages" : 0,
"eviction server unable to reach eviction goal" : 0,
"internal pages split during eviction" : 0,
"leaf pages split during eviction" : 0,
"pages walked for eviction" : 0,
"eviction worker thread evicting pages" : 0,
"in-memory page splits" : 0,
"in-memory page passed criteria to be split" : 0,
"lookaside table insert calls" : 0,
"lookaside table remove calls" : 0,
"percentage overhead" : 8,
"tracked dirty pages in the cache" : 0,
"pages currently held in the cache" : 47,
"pages read into cache" : 43,
"pages read into cache requiring lookaside entries" : 0,
"pages written from cache" : 13,
"page written requiring lookaside records" : 0,
"pages written requiring in-memory restoration" : 0
},
"connection" : {
"pthread mutex condition wait calls" : 6755705,
"files currently open" : 27,
"memory allocations" : 2046182,
"memory frees" : 2044869,
"memory re-allocations" : 531046,
"total read I/Os" : 936,
"pthread mutex shared lock read-lock calls" : 266348,
"pthread mutex shared lock write-lock calls" : 67963,
"total write I/Os" : 39
},
"cursor" : {
"cursor create calls" : 70,
"cursor insert calls" : 25,
"cursor next calls" : 3113,
"cursor prev calls" : 2919,
"cursor remove calls" : 1,
"cursor reset calls" : 171656,
"cursor restarted searches" : 0,
"cursor search calls" : 168752,
"cursor search near calls" : 2902,
"truncate calls" : 0,
"cursor update calls" : 0
},
"data-handle" : {
"connection data handles currently active" : 24,
"session dhandles swept" : 0,
"session sweep attempts" : 21,
"connection sweep dhandles closed" : 0,
"connection sweep candidate became referenced" : 0,
"connection sweep dhandles removed from hash list" : 3,
"connection sweep time-of-death sets" : 22,
"connection sweeps" : 17279
},
"log" : {
"total log buffer size" : 33554432,
"log bytes of payload data" : 4111,
"log bytes written" : 5504,
"yields waiting for previous log file close" : 0,
"total size of compressed records" : 3967,
"total in-memory size of compressed records" : 6785,
"log records too small to compress" : 6,
"log records not compressed" : 0,
"log records compressed" : 5,
"log flush operations" : 969556,
"maximum log file size" : 104857600,
"pre-allocated log files prepared" : 2,
"number of pre-allocated log files to create" : 2,
"pre-allocated log files not ready and missed" : 1,
"pre-allocated log files used" : 0,
"log release advances write LSN" : 5,
"records processed by log scan" : 10,
"log scan records requiring two reads" : 4,
"log scan operations" : 3,
"consolidated slot closures" : 2327947,
"written slots coalesced" : 0,
"logging bytes consolidated" : 5120,
"consolidated slot joins" : 11,
"consolidated slot join races" : 0,
"busy returns attempting to switch slots" : 0,
"consolidated slot join transitions" : 2327947,
"consolidated slot unbuffered writes" : 0,
"log sync operations" : 7,
"log sync_dir operations" : 1,
"log server thread advances write LSN" : 2,
"log write operations" : 11,
"log files manually zero-filled" : 0
},
"reconciliation" : {
"pages deleted" : 0,
"fast-path pages deleted" : 0,
"page reconciliation calls" : 12,
"page reconciliation calls for eviction" : 0,
"split bytes currently awaiting free" : 0,
"split objects currently awaiting free" : 0
},
"session" : {
"open cursor count" : 20,
"open session count" : 16
},
"thread-yield" : {
"page acquire busy blocked" : 0,
"page acquire eviction blocked" : 0,
"page acquire locked blocked" : 0,
"page acquire read blocked" : 0,
"page acquire time sleeping (usecs)" : 0
},
"transaction" : {
"transaction begins" : 11617,
"transaction checkpoints" : 2900,
"transaction checkpoint generation" : 2900,
"transaction checkpoint currently running" : 0,
"transaction checkpoint max time (msecs)" : 595,
"transaction checkpoint min time (msecs)" : 3,
"transaction checkpoint most recent time (msecs)" : 4,
"transaction checkpoint total time (msecs)" : 12083,
"transactions committed" : 3,
"transaction failures due to cache overflow" : 0,
"transaction range of IDs currently pinned by a checkpoint" : 0,
"transaction range of IDs currently pinned" : 0,
"transaction range of IDs currently pinned by named snapshots" : 0,
"transactions rolled back" : 11614,
"number of named snapshots created" : 0,
"number of named snapshots dropped" : 0,
"transaction sync calls" : 0
},
"concurrentTransactions" : {
"write" : {
"out" : 0,
"available" : 128,
"totalTickets" : 128
},
"read" : {
"out" : 0,
"available" : 128,
"totalTickets" : 128
}
}
},
"writeBacksQueued" : false,
"mem" : {
"bits" : 64,
"resident" : 7,
"virtual" : 2513,
"supported" : true,
"mapped" : 0,
"mappedWithJournal" : 0
},
"metrics" : {
"commands" : {
"buildInfo" : {
"failed" : NumberLong(0),
"total" : NumberLong(2)
},
"getLog" : {
"failed" : NumberLong(0),
"total" : NumberLong(2)
},
"isMaster" : {
"failed" : NumberLong(0),
"total" : NumberLong(10)
},
"listCollections" : {
"failed" : NumberLong(0),
"total" : NumberLong(1)
},
"listDatabases" : {
"failed" : NumberLong(0),
"total" : NumberLong(2)
},
"replSetGetStatus" : {
"failed" : NumberLong(2),
"total" : NumberLong(2)
},
"serverStatus" : {
"failed" : NumberLong(0),
"total" : NumberLong(1)
},
"whatsmyuri" : {
"failed" : NumberLong(0),
"total" : NumberLong(2)
}
},
"cursor" : {
"timedOut" : NumberLong(0),
"open" : {
"noTimeout" : NumberLong(0),
"pinned" : NumberLong(0),
"total" : NumberLong(0)
}
},
"document" : {
"deleted" : NumberLong(0),
"inserted" : NumberLong(0),
"returned" : NumberLong(0),
"updated" : NumberLong(0)
},
"getLastError" : {
"wtime" : {
"num" : 0,
"totalMillis" : 0
},
"wtimeouts" : NumberLong(0)
},
"operation" : {
"fastmod" : NumberLong(0),
"idhack" : NumberLong(0),
"scanAndOrder" : NumberLong(0),
"writeConflicts" : NumberLong(0)
},
"queryExecutor" : {
"scanned" : NumberLong(0),
"scannedObjects" : NumberLong(0)
},
"record" : {
"moves" : NumberLong(0)
},
"repl" : {
"executor" : {
"counters" : {
"eventCreated" : 0,
"eventWait" : 0,
"cancels" : 0,
"waits" : 0,
"scheduledNetCmd" : 0,
"scheduledDBWork" : 0,
"scheduledXclWork" : 0,
"scheduledWorkAt" : 0,
"scheduledWork" : 0,
"schedulingFailures" : 0
},
"queues" : {
"networkInProgress" : 0,
"dbWorkInProgress" : 0,
"exclusiveInProgress" : 0,
"sleepers" : 0,
"ready" : 0,
"free" : 0
},
"unsignaledEvents" : 0,
"eventWaiters" : 0,
"shuttingDown" : false,
"networkInterface" : "NetworkInterfaceASIO inShutdown: 0"
},
"apply" : {
"batches" : {
"num" : 0,
"totalMillis" : 0
},
"ops" : NumberLong(0)
},
"buffer" : {
"count" : NumberLong(0),
"maxSizeBytes" : 268435456,
"sizeBytes" : NumberLong(0)
},
"network" : {
"bytes" : NumberLong(0),
"getmores" : {
"num" : 0,
"totalMillis" : 0
},
"ops" : NumberLong(0),
"readersCreated" : NumberLong(0)
},
"preload" : {
"docs" : {
"num" : 0,
"totalMillis" : 0
},
"indexes" : {
"num" : 0,
"totalMillis" : 0
}
}
},
"storage" : {
"freelist" : {
"search" : {
"bucketExhausted" : NumberLong(0),
"requests" : NumberLong(0),
"scanned" : NumberLong(0)
}
}
},
"ttl" : {
"deletedDocuments" : NumberLong(0),
"passes" : NumberLong(2901)
}
},
"ok" : 1
}
``
看看有哪些库
show dbs;
admin 0.000GB
local 0.000GB
restfiddle 0.001GB
#use命令
MongoDB 用
use + 数据库名称
的方式来创建数据库。use 会创建一个新的数据库，如果该数据库存在，则返回这个数据库。」
例子1. 創建 root 用戶名密碼
####Step1.首先，切换到admin db (schema):
use admin;
switched to db admin
####Step2.在該 schema 下面設置用戶名，密碼：
db.createUser({ user: “root”,pwd: “root”,customData:{name:”root”},roles:[{ role: “userAdminAnyDatabase”,db: “admin” }]})
Successfully added user: {
“user” : “root”,
“customData” : {
“name” : “root”
},
“roles” : [
{
“role” : “userAdminAnyDatabase”,
“db” : “admin”
}
]
}
db.auth(‘root’,’root’)
1
####Step3.给restfiddle库权限
var r =
{
“_id”: “restfiddle.root”,
“user”: “root”,
“db”: “restfiddle”,
“credentials”: {
“SCRAM-SHA-1”: {
“iterationCount”: 10000,
“salt”: “riZjwBYHvkcV99typ8BRMA==”,
“storedKey”: “E2QOruLrBNXD1mlQTX0TQogL/ws=”,
“serverKey”: “JEQhfa/5×7+aNzKrFvKRkctXXfQ=”
}
},
“roles”: [
{
“role”: “dbOwner”,
“db”: “restfiddle”
},
{
“role”: “read”,
“db”: “restfiddle”
},
{
“role”: “readWrite”,
“db”: “restfiddle”
}
]
}
db.system.users.insert(r)
#[Database Operations](https://docs.mongodb.com/manual/reference/command/?spm=5176.100239.blogcont68925.15.OLu8c1#database-operations)
#查看数据库的文档（json document）,集合(collection)结构
我们切换到库use restfiddle,看一下当前库的状态：
use restfiddle;
switched to db restfiddle
db.stats()
{
“db” : “restfiddle”,
“collections” : 14,
“objects” : 298,
“avgObjSize” : 362.18120805369125,
“dataSize” : 107930,
“storageSize” : 372736,
“numExtents” : 0,
“indexes” : 15,
“indexSize” : 339968,
“ok” : 1
}
查看库restfiddle有哪些集合：
db
restfiddle
show collections;
EntityAuth
activityLog
baseNode
config
conversation
httpRequestHeader
oAuth2
project
rfRequest
rfResponse
runnerLog
tag
user
workspace
查看user集合里面有哪些json document：
db.user.find();
{ “_id” : ObjectId(“575fa8a2ba637304fffbad5e”), “_class” : “com.restfiddle.entity.User”, “password” : “$2a$10$JzistJ7qIP80KMYwSqSu7uShUGn4bg/m.u0/51HcKHVIui/URgbTi”, “email” : “rf@example.com“, “name” : “RF Admin”, “status” : “ACTIVE”, “version” : NumberLong(0) }
{ “_id” : ObjectId(“575fa8a2ba637304fffbad5f”), “_class” : “com.restfiddle.entity.User”, “password” : “$2a$10$eyrBDJyNepEPsX3qTUveqeKNxYFq/nQq4sTixY/nRZhFynTW9izxm”, “email” : “anuja@example.com“, “name” : “Anuja Kumar”, “status” : “ACTIVE”, “version” : NumberLong(0) }
db.user.find().pretty();
{
“_id” : ObjectId(“575fa8a2ba637304fffbad5e”),
“_class” : “com.restfiddle.entity.User”,
“password” : “$2a$10$JzistJ7qIP80KMYwSqSu7uShUGn4bg/m.u0/51HcKHVIui/URgbTi”,
“email” : “rf@example.com“,
“name” : “RF Admin”,
“status” : “ACTIVE”,
“version” : NumberLong(0)
}
{
“_id” : ObjectId(“575fa8a2ba637304fffbad5f”),
“_class” : “com.restfiddle.entity.User”,
“password” : “$2a$10$eyrBDJyNepEPsX3qTUveqeKNxYFq/nQq4sTixY/nRZhFynTW9izxm”,
“email” : “anuja@example.com“,
“name” : “Anuja Kumar”,
“status” : “ACTIVE”,
“version” : NumberLong(0)
}
我们看到，json的pretty()函数使得输出更好阅读。
#主键_id唯一性
我们往user集里面插入一条记录：
var newUser = {
… “_id” : ObjectId(“575fa8a2ba637304fffbad5e”),
… “_class” : “com.restfiddle.entity.User”,
… “password” : “$2a$10$JzistJ7qIP80KMYwSqSu7uShUGn4bg/m.u0/51HcKHVIui/URgbTi”,
… “email” : “rf@example.com“,
… “name” : “RF Admin”,
… “status” : “ACTIVE”,
… “version” : NumberLong(0)
… }
db.user.insert(newUser)
WriteResult({
“nInserted” : 0,
"writeError" : {
"code" : 11000,
"errmsg" : "E11000 duplicate key error collection: restfiddle.user index: _id_ dup key: { : ObjectId('575fa8a2ba637304fffbad5e') }"
}
})
看到了，提示我们：
> "E11000 duplicate key error collection: restfiddle.user index: _id_ dup key: { : ObjectId('575fa8a2ba637304fffbad5e') }"
这个提示，告诉我们，在mongoDB中，集合里面的文档json的主键_id是唯一的。
#插入一条json
db.user.find();
{ “_id” : ObjectId(“575fa8a2ba637304fffbad5e”), “_class” : “com.restfiddle.entity.User”, “password” : “$2a$10$JzistJ7qIP80KMYwSqSu7uShUGn4bg/m.u0/51HcKHVIui/URgbTi”, “email” : “rf@example.com“, “name” : “RF Admin”, “status” : “ACTIVE”, “version” : NumberLong(0) }
{ “_id” : ObjectId(“575fa8a2ba637304fffbad5f”), “_class” : “com.restfiddle.entity.User”, “password” : “$2a$10$eyrBDJyNepEPsX3qTUveqeKNxYFq/nQq4sTixY/nRZhFynTW9izxm”, “email” : “anuja@example.com“, “name” : “Anuja Kumar”, “status” : “ACTIVE”, “version” : NumberLong(0) }
db.user.insert({‘name’:’Jason Chen’,’status’:’ACTIVE’})
db.user.find().pretty();
{
“_id” : ObjectId(“575fa8a2ba637304fffbad5e”),
“_class” : “com.restfiddle.entity.User”,
“password” : “$2a$10$JzistJ7qIP80KMYwSqSu7uShUGn4bg/m.u0/51HcKHVIui/URgbTi”,
“email” : “rf@example.com“,
“name” : “RF Admin”,
“status” : “ACTIVE”,
“version” : NumberLong(0)
}
{
“_id” : ObjectId(“575fa8a2ba637304fffbad5f”),
“_class” : “com.restfiddle.entity.User”,
“password” : “$2a$10$eyrBDJyNepEPsX3qTUveqeKNxYFq/nQq4sTixY/nRZhFynTW9izxm”,
“email” : “anuja@example.com“,
“name” : “Anuja Kumar”,
“status” : “ACTIVE”,
“version” : NumberLong(0)
}
{
“_id” : ObjectId(“58cfeededc2042106f53c868”),
“name” : “Jason Chen”,
“status” : “ACTIVE”
}
我们可以看出，主键_id是每次插入的时候，自动生成的。那么，生成的算法是怎样的呢？
var id=new ObjectId();
id
ObjectId(“58cfefcddc2042106f53c869”)
参考：[MongoDB ObjectId详解及使用](http://www.jianshu.com/p/dd63b93a5955)