[MongoDB] Update Modifiers / Part.1 - $inc

Written by cinema4d

Sometimes you may want to modify only a certain portion of document.

Using update modifiers you can do that by atomic level such as altering, adding or removing keys and even manipulating arrays and embedded documents.

Assume that you have three webpages to manage and you are going to update pageviews - automatically increase by 1 when visiting.

Type the following for data preparations :

// user DB "foobar"
use foobar

// define webpage1
var page1 = {"url" : "www.gchoi.net", "pageviews" : 100}
// define webpage2
var page2 = {"url" : "www.google.com", "pageviews" : 1000}
// define webpage3
var page3 = {"url" : "www.apple.com", "pageviews" : 500}

// insert items into DB
db.analytics.insert(page1)
db.analytics.insert(page2)
db.analytics.insert(page3)
db.analytics.find()

Increase pageviews of url "www.gchoi.net" by 1 :

// increase pageviews of url "www.gchoi.net" by 1 
db.analytics.update({"url" : "www.gchoi.net"},{"$inc" : {"pageviews" : 1}})
db.analytics.findOne({"url" : "www.gchoi.net"})