It is absolutely introductory guidance to NOSQL and Mongo db for absolutely begineers

1. Beginner’s Guide to Concepts
of NOSQL and MongoDB
Documented By: - Maulin Shah

2. Purpose
Purpose of writing this document is to guide beginners to NoSQL concepts and MongoDB database.
Introduction
In recent years as internet and new technologies has become more accessible to people amount of data
that was being generated in 1990’s in one year is now in 2016 being generated in one hour and maybe
less time than that. And this rate is increasing rapidly every day. But, traditional methods and
technologies of collecting and processing data (Like SQL, and different frameworks) were not designed
to handle this huge amount of data. So, new methods and technologies has become necessity of time.
Because of that we are getting to see new technologies like Hadoop, NoSQL, etc. which are specially
designed to handle these amount of data.
History of database technologies
What is database and Database Management System (DBMS)?
Database technologies are collection of organized data. In this type of software data is collected as
schemas and tables. Database management system is an application that interacts with users. User
types their requests in form of query and DBMS process it and give appropriate output to user.
Three main era based models in database technology
1) Navigational (1960-1970)
2) Relational(SQL)(1970 - 2000)
3) Post-relational (NoSQL) (2000 - ongoing)
Relational database (RDBMS) was most successful data model till 2000s.
Shortcomings of RDBMS
1) Inability to handle unstructured/semi-structured data. Because as internet has expanded year over
year more unstructured/semi-structured data is being produced and RDBMS cannot handle that.
2) CRUD operations are not fast enough to give results and are costly operations as it has to deal with
joins and maintaining relationship among different data.
3) Because of Schema structure it is hard to scale out RDBMS.
To overcome these shortcomings NoSQL databases were introduced
NoSQL (Not Only SQL)
NoSQL database is provided for distributed data stores where there is need for large scale of data
storing needed. Because, they do not require fixed schemas, avoid join operations, and scale data
horizontally. In NoSQL database tables stored as ASCII files, tuple represented as row and fields are
separated with tabs.
Type of NoSQL databases
1) Key-Value Oriented (Radis, Riak )
2) Column Oriented (HBase, Cassandra)
3) Document Oriented (MongoDB, CouchDB)

3. 4) Graph data Oriented (Neo4j)
Key-Value Oriented
In this type of database client get, put or delete value for a key. Here Value is Binary Large Object which
only cares about data and not inside it, it is responsibility of application to understand what exactly is
stored.
Column Oriented
In this type of database, databases are based on column and every column is considered individually.
Here values of single column are stored adjacently. Data maintained by columns are in the form of
column – specific files.
Document Oriented
In this type of database documents are mainly stored in value part of key/value store. These databases
are hierarchical tree data structures that can have maps, collections and scalar values.
Graph Oriented
It uses graph structure to generate output of given query. It is mainly used for storing node data and
relationships between these nodes. Defining and finding relationship is very quick and easy in this type
of database.
CAP Theorem
It states that any distributed system; we should have three aspects C (consistency), A (Availability), P
(Partition tolerance). But unfortunately we can have any two at same time in a distributed system.
Consistency – every user should be able to see same data after execution of an operation.
Availability – Less or no downtime.
Partition Tolerance – system should work properly even though communication among server is not
reliable.
Sharding in NoSQL database
We can define it as a partitioning scheme for large databases distributed across various servers and
responsible for giving high performance and scalability. It Divides database into smaller parts (shards)
and replicates it across different servers.

4. MongoDB
Learning MongoDB is quite easy and fun. MongoDB is Document-Oriented database; it is open source
NoSQL database. We can use it as alternative of RDBMS. It can give high performance by using with
more specialized NoSQL databases.
Conceptual Understanding of MongoDB
1) MongoDB has same concept like schema in Oracle SQL; within a MongoDB instance (like SQL
schema) you can have zero or more database, each acting as high level container for everything else.
2) Collection in MongoDB is same as tables in RDBMS. MongoDB can have zero or more collection in it.
3) Document is MongoDB can be seen as row in RDBMS. Collections are made of zero or more
documents.
4) Fields in MongoDB can be seen as Column in RDBMS. Document can have zero or more fields in it.
5) Indexes concept is same as in SQL.
6) Cursor in MongoDB is new concept which is used when we ask MongoDB for data it returns a pointer
to a result set which is called cursor.
Basic operations in MongoDB
Let’s start playing with MongoDB.
Insert()
db.User.insert[{_id=1,FName:”Maulin”,Lname:”Shah”,address:{street:”Shyamalcrossroad”,
city: “Ahmedabad”, zipCode:380015},Phone:[8980162257,9409032647]},
{_id=2,FName:”Paresh”,Lname:”Patel”,address:{street:”kharadigate”, city: “Surat”,
zipCode:300018},Phone:[8089612275]}]
If we do not have any collection insert() will create one.(!!! Interesting?), here, if we don’t specify id field
MongoDB will generate id by itself as Object id. (wow!!)
DATABASE
COLLECTIONS
DOCUMENTS
FIELDS

5. Find()
It works like select statement in SQL.
Example
db.example.find() -> select * from example;
db.example.find({Age:24}) -> select * from users where Age=24;
comparison operators
List of operators
$ne -> not equal to, $gt -> greater than, $gte -> greater than equal to, $lt -> less than, $lte -> less than
equal to , $in, $nin -> not in, $mod, $exists
example
db.example.find({Name:{$ne:”Maulin”}})
above query will return all documents from user collection where name is Not Maulin.
Logical operators
List of operators
$And, $or
Example
Db.example.find({Name:”Maulin”,Age:24}) -> It will return all documents where Name is Maulin AND
Age is 24.
Easy!!! Right. So, this is it from my side. Learning new technology is not always hard.
** ALL THE BEST **
** HAPPY LEARNING **