6.mongo命令提示符帮助

6.mongo命令提示符帮助

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① mongo命令行参数帮助

通过--help参数显示命令行帮助信息

mongo --help

显示:

MongoDB shell version: 2.0.4usage: 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 9999options:  --shell               run the shell after executing files  --nodb                don't connect to mongod on startup - no 'db address'                        arg expected  --norc                开始不执行".mongorc.js"文件  --quiet               安静模式  --port arg            端口  --host arg            IP  --eval arg            运行javascript脚本  -u [ --username ] arg 用户名  -p [ --password ] arg 密码  -h [ --help ]         显示这个帮助信息  --version             版本号  --verbose             increase verbosity  --ipv6                开启IPv6支持(默认关闭)

② mongo指令帮助

通过命令提示符连上mongo数据库后,可以输入help来显示命令提示符帮助.

help

会显示:

db.help()                    数据库方法帮助信息db.mycoll.help()             集合方法帮助信息rs.help()                    help on replica set methodshelp admin                   管理员帮助信息help connect                 连接数据库帮助help keys                    快捷键help misc                    杂项信息帮助help mr                      mapreduce帮助show dbs                     显示全部数据库名show collections             显示当前数据库中的全部集合名show users                   显示当前数据库的全部用户show profile                 show most recent system.profile entries with time >= 1msshow logs                    显示可以连接的日志(`logger`)名show log [name]              输出内存中的最近log的片段, 默认输出`global`use                 设定当前数据库db.foo.find()                显示集合`foo`中的对象列表db.foo.find( { a : 1 } )     查询foo集合中`a == 1`的对象it                           输入it, 继续迭代显示结果, 输出更多结果DBQuery.shellBatchSize = x   设置显示结果条数exit                         退出命令行

③ 数据库帮助

1.显示全部数据库

show dbs

2.显示部数据操作帮助

db.help()

3.显示方法的实现

显示一个数据的方法的具体实现，输入db.不带(). 例如:

db.updateUser

显示:

test.updateUser

④ 集合帮助

1.显示全部集合

show collections

2.显示集合帮助

db.collection.help()

显示

db.collection.find().help() - show DBCursor helpdb.collection.count()db.collection.dataSize()db.collection.distinct( key ) - eg. db.collection.distinct( 'x' )db.collection.drop() drop the collectiondb.collection.dropIndex(name)db.collection.dropIndexes()db.collection.ensureIndex(keypattern[,options]) - options is an object with these possible fields: name, unique, dropDupsdb.collection.reIndex()db.collection.find([query],[fields]) - query is an optional query filter. fields is optional set of fields to return.                                              e.g. db.collection.find( {x:77} , {name:1, x:1} )db.collection.find(...).count()db.collection.find(...).limit(n)db.collection.find(...).skip(n)db.collection.find(...).sort(...)db.collection.findOne([query])db.collection.findAndModify( { update : ... , remove : bool [, query: {}, sort: {}, 'new': false] } )db.collection.getDB() get DB object associated with collectiondb.collection.getIndexes()db.collection.group( { key : ..., initial: ..., reduce : ...[, cond: ...] } )db.collection.mapReduce( mapFunction , reduceFunction ,  )db.collection.remove(query)db.collection.renameCollection( newName ,  ) renames the collection.db.collection.runCommand( name ,  ) runs a db command with the given name where the first param is the collection namedb.collection.save(obj)db.collection.stats()db.collection.storageSize() - includes free space allocated to this collectiondb.collection.totalIndexSize() - size in bytes of all the indexesdb.collection.totalSize() - storage allocated for all data and indexesdb.collection.update(query, object[, upsert_bool, multi_bool])db.collection.validate(  ) - SLOWdb.collection.getShardVersion() - only for use with shardingdb.collection.getShardDistribution() - prints statistics about data distribution in the cluster

3.显示集合方法实现

显示方法实现输入db.., 不带(). 例如输入:

db.collection.save

显示:

function (obj) {    if (obj == null || typeof obj == "undefined") {        throw "can't save a null";    }    if (typeof obj == "number" || typeof obj == "string") {        throw "can't save a number or string";    }    if (typeof obj._id == "undefined") {        obj._id = new ObjectId;        return this.insert(obj);    } else {        return this.update({_id:obj._id}, obj, true);    }}

⑤ cursor帮助

当你在mongo命令行使用find()方法时, 可以使用很多cursor方法来修改find()行为和结果.

• 显示find()方法可用的修改器和cursor处理方法

  db.collection.find().help()

显示:

> db.collection.find().help()find() modifiers    .sort( {...} )    .limit( n )    .skip( n )    .count() - total # of objects matching query, ignores skip,limit    .size() - total # of objects cursor would return, honors skip,limit    .explain([verbose])    .hint(...)    .showDiskLoc() - adds a $diskLoc field to each returned objectCursor methods    .forEach( func )    .map( func )    .hasNext()    .next()

• 看cursor方法的实现, 输入db..find()., 不包含(). 例如:

db.collection.find().toArray

显示:

> db.collection.find().toArrayfunction () {    if (this._arr) {        return this._arr;    }    var a = [];    while (this.hasNext()) {        a.push(this.next());    }    this._arr = a;    return a;}

常用的cursor方法

• hasNext() 查询cursor是否还有数据.

• next() 返回下一个数据对象, 并且cursor指向位置加1.

• forEach(

  ) 方法遍历执行全部结果. 只有1参数, 迭代器中指向的对象.

⑥ 包装对象帮助

可以通过输入help misc来获取对象包装类.

help misc

显示:

> help misc    b = new BinData(subtype,base64str)  create a BSON BinData value    b.subtype()                         the BinData subtype (0..255)    b.length()                          length of the BinData data in bytes    b.hex()                             the data as a hex encoded string    b.base64()                          the data as a base64 encoded string    b.toString()    b = HexData(subtype,hexstr)         create a BSON BinData value from a hex string    b = UUID(hexstr)                    create a BSON BinData value of UUID subtype    b = MD5(hexstr)                     create a BSON BinData value of MD5 subtype    o = new ObjectId()                  create a new ObjectId    o.getTimestamp()                    return timestamp derived from first 32 bits of the OID    o.isObjectId()    o.toString()    o.equals(otherid)

⑦ 参考文章

官方文档