查看命令的方式：

1.在shell中运行db.listCommands()

2.在浏览器中访问管理员接口：http://ipaddress:28017/_commands

下面介绍在Mongodb中最经常使用的命令，具体如下：

命令：buildInfo

格式：{"buildInfo":1}

介绍：管理专用命令，返回Mongodb服务器的版本号和主机的操作系统。

示例：

Shell代码

> db.runCommand({"buildInfo":1})
{
"version" : "2.0.6",
"gitVersion" : "e1c0cbc25863f6356aa4e31375add7bb49fb05bc",
"sysInfo" : "Linux domU-12-31-39-01-70-B4 2.6.21.7-2.fc8xen #1 SMP Fri Feb 15 12:39:36 EST 2008 i686 BOOST_LIB_VERSION=1_41",
"versionArray" : [
2,
0,
6,
0
],
"bits" : 32,
"debug" : false,
"maxBsonObjectSize" : 16777216,
"ok" : 1
}

命令：collStats

格式：{"collStats":collection}

介绍：返回指定集合的统计信息，包括数据大小、已分配的存储空间和索引的大小。

示例：

Shell代码

> db.runCommand({"collStats":"users"})
{
"ns" : "test.users",
"count" : 3,
"size" : 508,
"avgObjSize" : 169.33333333333334,
"storageSize" : 4096,
"numExtents" : 1,
"nindexes" : 2,
"lastExtentSize" : 4096,
"paddingFactor" : 1.51,
"flags" : 0,
"totalIndexSize" : 16352,
"indexSizes" : {
"_id_" : 8176,
"name_1" : 8176
},
"ok" : 1
}

命令：distinct

格式：{"distinct":collection,"key":key,"query":query}

介绍：列出指定集合中满足查询条件的文档的指定键的所有不同值

示例：

Shell代码

> db.runCommand({"distinct":"foo","key":"name","query":{"age":{"$gt":20}}})
{
"values" : [
"gongyong",
"chenzhou",
"yixin"
],
"stats" : {
"n" : 4,
"nscanned" : 6,
"nscannedObjects" : 6,
"timems" : 50,
"cursor" : "BasicCursor"
},
"ok" : 1
}

命令：drop

格式：{"drop":collection}

介绍：删除集合的所有数据

示例：

Shell代码

> db.bbb.save({"x":1,"y":2})
#先往bbb中存一条记录
> db.bbb.find() #查询bbb中的数据
{ "_id" : ObjectId("5027d919831a10b0f6e61385"), "x" : 1, "y" : 2 }
#使用drop命令删除bbb集合中的数据
> db.runCommand({"drop":"bbb"})
{
"nIndexesWas" : 1,
"msg" : "indexes dropped for collection",
"ns" : "test.bbb",
"ok" : 1
}
> db.bbb.find() #再次查询，结果为空

命令：dropDatabase

格式：{"dropDatabase":1}

介绍：删除当前数据库中的所有数据

示例：略

命令：dropIndexes

格式：{"dropIndexes":collection,"index":name}

介绍：删除集合里面名称为name的索引，如果名称为"*"，则删除全部索引。

示例：
Shell代码

> db.system.indexes.find()
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.foo", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.users", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.games", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.blog.post", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.lists", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.math", "name" : "_id_" }
{ "v" : 1, "key" : { "name" : 1 }, "ns" : "test.users", "name" : "name_1" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.map", "name" : "_id_" }
{ "v" : 1, "key" : { "gps" : "2d" }, "ns" : "test.map", "name" : "gps_", "min" : -180, "max" : 181 }
> db.runCommand({"dropIndexes":"users","index":"name_1"})
{ "nIndexesWas" : 2, "ok" : 1 }
> db.system.indexes.find()
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.foo", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.users", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.games", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.blog.post", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.lists", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.math", "name" : "_id_" }
{ "v" : 1, "key" : { "_id" : 1 }, "ns" : "test.map", "name" : "_id_" }
{ "v" : 1, "key" : { "gps" : "2d" }, "ns" : "test.map", "name" : "gps_", "min" : -180, "max" : 181 }

命令：findAndModify

格式：

介绍：查找并修改

示例：

Shell代码

> db.foo.find({"name":"yixin"})
{ "_id" : ObjectId("5027d84b831a10b0f6e61384"), "name" : "yixin", "age" : 23 }
> db.runCommand({"findAndModify":"foo",
... "query":{"name":"yixin"},
... "update":{"$inc":{"age":1}}}) #把name为yixin的记录中age值加1
{
"lastErrorObject" : {
"updatedExisting" : true,
"n" : 1,
"connectionId" : 2,
"err" : null,
"ok" : 1
},
"value" : {
"_id" : ObjectId("5027d84b831a10b0f6e61384"),
"name" : "yixin",
"age" : 23
},
"ok" : 1
}
> db.foo.find({"name":"yixin"})
{ "_id" : ObjectId("5027d84b831a10b0f6e61384"), "name" : "yixin", "age" : 24 }

命令：getLastError

格式：{"getLastError":1[ , "w":w[ , "wtimeout":timeout}

介绍：查看对本集合执行的最后一次操作的错误信息或者其它状态信息。在w台服务器复制集合的最后操作之前，这个命令会阻塞。

示例：
Shell代码

> db.runCommand({"getLastError":1})
{ "n" : 0, "connectionId" : 2, "err" : null, "ok" : 1 }

命令：isMaster

格式：{"isMaster":1}

介绍：检查本服务器是主服务器还是从服务器

示例：
Shell代码

> db.runCommand({"isMaster":1})
{ "ismaster" : true, "maxBsonObjectSize" : 16777216, "ok" : 1 }

命令：listCommands

格式：{"listCommands":1}

介绍：返回所有可以在服务器上运行的命令及相关信息。

示例： 返回结果太多，示例就省略了

命令：listDatabases

格式：{"listDatabases":1}

介绍：管理专用命令，列出服务器上所有的数据库

示例：
Shell代码

> db.runCommand({"listDatabases":1})
{ "errmsg" : "access denied; use admin db", "ok" : 0 }
#报错，提示访问被拒绝，要求必须使用admin数据库
> use admin #切换到admin数据库
switched to db admin
> db.runCommand({"listDatabases":1})
{
"databases" : [
{
"name" : "test",
"sizeOnDisk" : 67108864,
"empty" : false
},
{
"name" : "results",
"sizeOnDisk" : 67108864,
"empty" : false
},
{
"name" : "admin",
"sizeOnDisk" : 1,
"empty" : true
},
{
"name" : "local",
"sizeOnDisk" : 1,
"empty" : true
}
],
"totalSize" : 134217728,
"ok" : 1
}

命令：ping

格式：{"ping":1}

介绍：检查服务器链接是否正常。即便服务器上锁了，这条命令也会立刻返回

示例：

Shell代码

> db.runCommand({"ping":1})
{ "ok" : 1 }

命令：renameCollection

格式：{"renameCollection":a,"to":b}

介绍：将集合a重命名为b，其中a和b都必须是完整的集合命名空间（例如"test.foo"代表test数据库中的foo集合）

示例：

Shell代码

> db.runCommand({"renameCollection":"foo","to":"foo_bak"})
{ "errmsg" : "access denied; use admin db", "ok" : 0 }
> use admin
switched to db admin
> db.runCommand({"renameCollection":"foo","to":"foo_bak"})
{
"errmsg" : "exception: source namespace does not exist",
"code" : 10026,
"ok" : 0
}
> db.runCommand({"renameCollection":"test.foo","to":"test.foo_bak"})
{ "ok" : 1 }
> db.foo_bak.find()
> use test
switched to db test
> db.foo_bak.find()
{ "_id" : ObjectId("502149203e2ff9961cc7b555"), "name" : "chenzhou" }
{ "_id" : ObjectId("502149353e2ff9961cc7b556"), "age" : 23 }
{ "_id" : ObjectId("5021495c3e2ff9961cc7b557"), "name" : "gongyong", "age" : 26 }
{ "_id" : ObjectId("50214ad63e2ff9961cc7b558"), "name" : "chenzhou", "age" : 22, "friends" : 500, "enemies" : 2 }
{ "_id" : 123, "x" : 1 }
{ "_id" : ObjectId("5027d84b831a10b0f6e61384"), "name" : "yixin", "age" : 24 }

命令：repairDatabase

格式：{"repairDatabase":1}

介绍：修复并压缩当前数据库，这个操作可能非常耗时。

示例：略

命令：serverStatus

格式：{"serverStatus":1}

介绍：返回这台服务器的管理统计信息。

示例：

Shell代码

> db.runCommand({"serverStatus":1})
{
"host" : "localhost.localdomain",
"version" : "2.0.6",
"process" : "mongod",
"uptime" : 3661,
"uptimeEstimate" : 2987,
"localTime" : ISODate("2012-08-12T17:07:05.076Z"),
"globalLock" : {
"totalTime" : 3659420009,
"lockTime" : 609397,
"ratio" : 0.00016652830188971076,
"currentQueue" : {
"total" : 0,
"readers" : 0,
"writers" : 0
},
"activeClients" : {
"total" : 0,
"readers" : 0,
"writers" : 0
}
},
"mem" : {
"bits" : 32,
"resident" : 45,
"virtual" : 158,
"supported" : true,
"mapped" : 64
},
"connections" : {
"current" : 1,
"available" : 818
},
"extra_info" : {
"note" : "fields vary by platform",
"heap_usage_bytes" : 491848,
"page_faults" : 0
},
"indexCounters" : {
"btree" : {
"accesses" : 1,
"hits" : 1,
"misses" : 0,
"resets" : 0,
"missRatio" : 0
}
},
"backgroundFlushing" : {
"flushes" : 60,
"total_ms" : 119,
"average_ms" : 1.9833333333333334,
"last_ms" : 0,
"last_finished" : ISODate("2012-08-12T17:06:05.816Z")
},
"cursors" : {
"totalOpen" : 0,
"clientCursors_size" : 0,
"timedOut" : 0
},
"network" : {
"bytesIn" : 7312,
"bytesOut" : 63515,
"numRequests" : 102
},
"opcounters" : {
"insert" : 2,
"query" : 29,
"update" : 1,
"delete" : 0,
"getmore" : 0,
"command" : 75
},
"asserts" : {
"regular" : 0,
"warning" : 0,
"msg" : 0,
"user" : 1,
"rollovers" : 0
},
"writeBacksQueued" : false,
"ok" : 1
}