mongo basic commad

mongoDB command for data operation

run mongo's shell

• assign a value to variable

>x = 200
200

• and cal it

>x/5
40

• you can use std lib of JavaScript

>Math.sin(Math.PI/2);
1
> new Date(2010/1/1);
ISODate("1970-01-01T00:00:02.010Z")
> "hello,world".replace("world","mongo");
hello,mongo

• and you can define a JS function and call it

> function factorial(n){
... if(n<=1) return 1;
... return n*factorial(n-1);
... }
> factorial(5);
120

mongoDB client

• test is mongo default db,mongo will connect to this database after shell started,you can use db to check which db in use

>db
test

• list all db

> show dbs
admin  0.000GB
local  0.000GB
test   0.000GB

• and switch your current db

> use local
switched to db local

• and you can use db.help() for db's help or db.mycoll.help() for collection's help

basic operation in mongo's shell

1. insert

• firstly. create a local variable like this

> person = {"name":"jiangbo",
... "sex":"man",
... "birth":new Date()}
{
	"name" : "jiangbo",
	"sex" : "man",
	"birth" : ISODate("2017-09-28T02:48:50.128Z")
}

• second. save the person variable into a collection by use method insert()

> db.people.insert(person);
WriteResult({ "nInserted" : 1 })

there is no collection named people before we insert person into collection people,when we insert,collection people was created. you can use show collections see all collection in current db.

2. find

• you can use find() to see collection's data.

> db.people.find()
{ "_id" : ObjectId("59cc658d9d608c39be913831"), "name" : "jiangbo", "sex" : "man", "birth" : ISODate("2017-09-28T02:48:50.128Z") }

3.update

method update accept tow argument at least. first argument is condition. second argument is new data. for example. add "friends" key for person and update it.

• first. alter person, add a key named "friends".

> person.friends=["xiaohua",
... "xiaohong"]
[ "xiaohua", "xiaohong" ]
> person
{
	"name" : "jiangbo",
	"sex" : "man",
	"birth" : ISODate("2017-09-28T02:48:50.128Z"),
	"friends" : [
		"xiaohua",
		"xiaohong"
	]
}

• second. replace old to new

> db.people.update({name:"jiangbo"},person)
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.people.find()
{ "_id" : ObjectId("59cc658d9d608c39be913831"), "name" : "jiangbo", "sex" : "man", "birth" : ISODate("2017-09-28T02:48:50.128Z"), "friends" : [ "xiaohua", "xiaohong" ] }

4. delete

use remove to remove doc from collection. the argument is condition for method remove

> db.people.remove({name:"jiangbo"})
WriteResult({ "nRemoved" : 1 })

command for db operation

• for start your mongodb shell,but make sure add your mongodb'path to profile

$ mongo

• for remote connection

$ mongo ${hostname}:${port}/${dbname}

• dump mongodb data

$ mongodump -h ${dbhost} -d ${dbname} -o ${dbdirectory}

• restore mongodb data

$ mongorestore -h ${hostname}:${port} -d dbname ${path}