# start mongodb server
$ mongod --dbpath=data/	

$ sudo service mongod start

#connect to remote server
$ mongo "mongodb://mongoserver.net:27017?replicaSet=Cluster0-shard-0" --authenticationDatabase admin --ssl --username user --password pwd

# connect to default local server
$mongo 	

# connect to default local server
$mongo 				- run mongo db shell

> use <db name>		- swith database or create database if not exist already
> db 				- to check currently selected database
> show dbs 			- check database list
> show collections	- show list of collection in current db
> db.dropDatabase()	- drop the database

> db.stats()

> db.help()

> db.creatCollection(name,option)

> db.<collection_name>.help()

> db.mycollection.insert({name:'movie name', releasedate:'date'});

#equality
{ "name"  : "search value" }

#less than  
{ "price" : {$lt : 50} }
# less than equal
{ "price" : {$lte : 50}}

# greater than
{ "price" : {$gt : 50} }
# greater than equal
{ "price" : {$gte : 50}}

# not equal
{ "price" : {$ne : 50} }

# And statement
{ 
	key1:value1, 
	key2:value2 
}

# OR statement
{
  $or: [
     {key1: value1}, {key2:value2}
  ]
}


# Array Exact Match
{ "amenities" : ["pool", "parking","wifi"]}

# Array with single element match
{ "amenities" : "wifi" }

# Array with position element
{ "amenities.0" : "pool"}

> db.myCollection.update(SELECTIOIN_CRITERIA, UPDATED_DATA)

e.g.
	> db.mycol.update({'title':'MongoDB Overview'}, {$set:{'title':'New MongoDB Tutorial'}})

- replace existing document with new one

> db.COLLECTION_NAME.save({_id:ObjectId(),NEW_DATA})

> db.COLLECTION_NAME.remove(DELLETION_CRITTERIA)

> db.COLLECTION_NAME.remove(DELETION_CRITERIA, 1)    - remove only one  

> db.COLLECTION_NAME.remove()		- remove all document

e.g.
	> db.Users.remove( { status : "D" } )

- select only necessary data rather than selecting whole of the data of document

> db.COLLECTION_NAME.find({},{ _id: 0, name :1})
				this will return only name parameter and hide the _id param

- limit the record to return 

> db.COLLECTION_NAME.find().limit(NUMBER)

- skip the record to return 

> db.COLLECTION_NAME.find().skip(NUMBER)

> db.COLLECTION_NAME.find().sort({KEY:1})

	  - 1 for ascending , -1 for descending

- Indexes support the efficient resolution of queries

> db.COLLECTION_NAME.ensureIndex({KEY:1})
		1 for create index in ascending order
		-1 for decending order
	* Optional option
		background Boolean
		unique		Boolean
		name 		name of index
		...

	Syntax
		db.<collection>.aggregate(aggregate_operation)
	e.g.
		db.myCol.aggregate([ { 
			$group : { _id : "$column1",  num : { $sum : 1}   }
		} ])

		simillar with
		select column1, count(*)
		from mycol
		group by column1

	@ Expression
		$sum
		$avg
		$min
		$max

> mongodump

-- Restore 
> mongorestore