Introduction to MongoDB

NoSQL

Before starting with the MongoDB introduction, let’s discuss NoSQL

• NoSQL (Not Only SQL) was started in 2009 and then rapidly started growing.
• It provides support to the storage and retrieval of data other than tabular relations.
• Currently there are more than 160 NoSQL databases. MongoDB is the leading NoSQL database

• NoSQL databases allow storing of data without any predefined schemas
• Primary goal of NoSQL databases is to provide horizontal scalability i.e. we can add a number of servers to handle large traffic.
• Relational     database (SQL) database use SQL to define and manipulate data whereas NoSQL uses unstructured query language such as JSON
• SQL databases: Oracle, MySQL, PostgreSQL etc.
• NoSQL databases: MongoDB, BigTable, Redis, RavenDb, Cassandra
• It is easy to store hierarchical data in NoSQL, Let’s discuss more MongoDB

MongoDB

• MongoDB is an open-source document-oriented NoSQL database that provides high performance, high availability, and automatic scaling
• This has been written in C++ and its created by 10 gen. The name MongoDB came from the word humongous means huge data.
• MongoDB works on concepts of collection and document. It stores data as a collection of name-value pairs. And it is a schema-less database

Example 

{“john”:1, “smith”: 2}

MongoDB uses BSON data format which is binary JSON (JavaScript Object Notion) for data storage and data transfer, BSON provides additional DATATypes

JSON is the syntax for storing and exchanging data, an alternative for XML, Language independent, and self-describing. JSON is built based on two structures

1.  Collection of name-value pair
2.  An ordered list of values

Example of document

     { rno : 1234

       name : Chris

       aggregate: 75

     }

MongoDBDatatypes

MongoDB supports a number of datatypes likes STRING, NUMBER, BOOLEAN, DATE, NULL, ARRAY, FLOAT,
Mapping of terms with RDBMS DB

Now we will look for more details on Documents and collection

Documents: 

• Document is a set of name-value pairs which can have dynamic schema
• MongoDB documents are BSON documents i.e. binary representation of JSON
• MongoDB instance may have zero or more documents
• Document is equivalent to RDBMS row 

Collection:

The collection is equivalent to RDBMS tables; one can have zero or more collections

A collection is group of documents

collection is schema-free.

Why MongoDB (Features of MongoDB)

With the use document instead of a relation database row, it’s very simple to represent complex hierarchical relationships with a single record (document).

No predefined schema, documents keys, and values not of fixed sizes.

 Easy scaling - as the amount of data is growing day by day it’s important to scale databases/servers. MongoDB was designed to scale out (sharing data across machines); MongoDB makes it easier to scale up data using multiple servers

 Supports Indexing, aggregation, special collection types, file storage (GRIDFS), replication, sharding (storing data across machines), auto-balancing of data across machines 

 Advantages over RDBMS

• schema-free
• no joins required
• relationship between objects not required
• easy to scale
• uses internal memory for operations which enables fast retrieval of data

watch out this space for more articles coming on MongoDB