Mondo DB useful commands for beginners. Adapted from a YouTube Video - https://www.youtube.com/watch?v=pWbMrx5rVBE

sample-mongo-commands.json

//after installing mondodb
//cd to the 'bin' directory of the mongodb folder
//run the following commands in the cmd (run as administrator -for Windows)
mongod --directoryperdb --dbpath C:\mongodb\data\db --logpath C:\mongodb\log\mongo.log --logappend --rest --install

//to start the mongodb service
net start MongoDB

//to enter mongodb service (this is necessary to start the mongo service)
mongo

//show all the databases
show dbs

//use the database that is named as "customers"
use customers

//to show all the databases available
db

//to create a user named "jatin" and password as "1234"
//with roles as rights alloted to the user
db.createUser({
	user:"jatin",
	pwd:"1234",
    roles: [ "readWrite", "dbAdmin" ]
});

//to create a collection similar to "tables" in the sql
//the collection here in named as 'customer'
db.createCollection('customer');

//to show all the collections
show collections

//to insert the data in the collection named "customers"
db.customers.insert({
	fname:"Jatin",
	lname:"Chauhan"
})

//to display the inserted data in the collection
db.customers.find();

//array to add multiple customers
db.customers.insert([{
	fname:"Abha",
	lname:"Chauhan"
},{
	fname:"Neha",
	lname:"Chauhan"
},{
	fname:"Poonam",
	lname:"Chauhan"
},{
	fname:"Pyare",
	mname:"Lal",
	lname:"Chauhan"
}
]);

//to display the data in an organized manner
db.customers.find().pretty();

//to update any data in the collection 
//(It will override the existing data)
db.customers.update({
	fname:"Jatin"
},{
	fname:"Josh",
	mname:"Smith",
	lname:"Dunn"
})

//to update the data in the collection 
//(Will not override the data once '$set' is used)
db.customers.update({
	fname:"Jatin"
},{
	$set:{
	gender:"male"
	}
})

//to inrement an integer value in the field
db.customers.update({
	fname:"Josh"
},{
	$inc:{age:1}
})

//to remove a field in the record of the collection
db.customers.update({
	fname:"Josh"
},{
	$unset:{age:1}
})

//to update the value and if the value 
//that doesn't exist in the field, add it
//using upsert
db.customers.update({
	fname:"Katy"
},{
	fname:"Katy",
	lname:"Perry",
	gender:"Female"
},{
	upsert: true
})

//renaming a 'field' in the collection
db.customers.update({
	fname:"Katy"
},{
	$rename:{
	"lname":"mname"
	}
})

//to remove a record from the collection (deletes all the one that matches)
db.customers.remove({
	fname:"Katy"
})

//to remove a record from the collection (deletes the first one one that matches)
db.customers.remove({
	fname:"Katy"
},{
	justOne: true
})

//to find a particular record in the collection (finds all that is related)
db.customers.find({fname:"Jatin"})

//using the $or operator to find more values
db.customers.find({$or:[{fname:"Jatin"},{fname:"Josh"}]})

//to use condition with find (eg $gt (greater than) $lt (less than))
//in this example we are finding age that is less than '40'
db.customers.find({
	age:{
	$lt:40
	}
})

//to find the sub-object from the record
//sub-object : refers to the sub values assigned to the objects
//note: we are using double quotes for the objects
db.customers.find({
	"address.city":"Boston"
})

//for quering the object of type array
db.customers.find({memberships:"mem1"})

//to sort the records in the collections
//  1: for ascending
db.customers.find().sort({lname:1})
// -1: for descending
db.customers.find().sort({lname:-1})

//count the documents
db.customers.find().count();

//count the documents with the condition (eg: sorting 'male' gender)
db.customers.find({gender:"male"}).count();

//setting limits in the 'find' (eg: top four doc's)
db.customers.find().limit(4);

//combining queries
db.customers.find().limit(4).sort({fname:1})

//using foreach loop with javascript to do more cool stuff
//In this example we are displaying all the 'fnames' in the record
db.customers.find().forEach(
	function(doc){
		print("Customers name: " + doc.fname)
 	})