Introduction to MongoDB

 What is MongoDB

•Source-available, cross-platform and document-oriented database program 

•Name derived from keyword “humongous” 

•Written in C++, JavaScript, Python

•Uses JSON-like documents with optional schemas 

•Developed by MongoDB Inc. and licensed under the Server Side Public License (SSPL)

 

History of MongoDB

•In 2007, “10gen” software company

•In 2009, company shifted to an open-source development model 

•In Feb 2009, MongoDB’s initial and official release 

•In 2013, 10gen changed its name to MongoDB Inc.

•In 2014, MongoDB acquired WiredTiger

Key Features of MongoDB 

•High Performance 

•Rich Query Language 

•High Availability 

•Horizontal Scalability 

•Support of multiple Storage Engine

RDBMS vs MongoDB

 

 

 

 

Introduction to CAP theorem

CAP theorem

• Consistency, Availability, Partition tolerance 

• Brewer’s Theorem after computer scientist Eric Brewer 

• A distributed system can deliver only two of three desired characteristics 

• In the presence of a network partition, one has to choose between consistency   and availability

 

CAP theorem

•Consistency– 

•All clients see the same data at the same time

•Every read receives the most recent write or an error

•Availability– 

•Any client making a request for data gets a response 

•Every request receives a (non-error) response

•Partition tolerance – 

•A communications break within a distributed system

•The system continues to operate despite messages being dropped (or delayed)

 

 Introduction to JSON 

•JavaScript Object Notation

•Simple associative containers 

•A string key is mapped to a value 

•Human and machine-readable

•Comparatively simple to implement support for 

•JavaScript became the default language of client-side web development 

•JSON shows up in many different 

cases:

 •APIs

 •Configuration files

 •Log messages 

•Database storage

 JSON Examples 

•Simple Key –Value pairs

 { 

“name”: “MongoDB”, 

“type” : “Document-based NoSQL Database” 

  }

•Key – Array value pairs 

{

 “name”: “MongoDB”,

 “tags” : [“Document”, “NoSQL”, “Database”, “Leaf”] 

} 

 

JSON Examples 

•Key – Embedded value pair 

{ 

"name" : {

 "first" : "John",

 "last" : “Adams" 

   }

 }

 

JSON Examples 

•Key –Array of Embedded value pairs 

{

 "awards" :[

 {"award" : "W.W. McDowell Award",

 "year" : 1967, 

"by" : "IEEE Computer Society"

 }, 

{"award" : "Draper Prize",

 "year" : 1993, 

"by" : "National Academy of Engineering" 

}

] }

 

MongoDB Document

•Data records as BSON documents 

•Composed of field-and-value pairs 

•Field can be any of the BSON data types 

•Value can be other documents, arrays, and arrays of documents 

•It is similar to JSON document 

•Can have more than one field with the same name•The maximum BSON document size is 16 megabytes.

•_id is primary key, auto-created