NoSQL database

  Data is everywhere, it is expanding with each passing day. Relational Database systems are kind of fixed and static. When we have something in abundance and without any standard formation, then the tables of relational database systems cry out.  So what to do with so many data integrations from several structured as well as unstructured sources. Well, the answer is to go for NoSQL (Not Only SQL). SQL is a structured query language that is used to query Relational Databases. However, NoSQL database does not contain data in the form of relations. Most of the NoSQL databases follow the JSON type structure to store data.    Formal Definition:      Guru99  provides a pretty nice definition for NoSQL databases: " NoSQL Database  is a non-relational Data Management System, that does not require a fixed schema. It avoids joins and is easy to scale. The major purpose of using a NoSQL database is for distributed data stores with humongous data storage needs. NoSQL is used for Big data an

Relational Data Model

In the previous blog post, we covered Data Modeling. We have seen that data modeling is really important before jumping into predictive modeling.  In this article, we will cover the Relational Data Model (RDM). Let's start from the very basics, relational means anything which is linked with some other thing. This link is called "Relationship". In RDM or RM there are major three types of relationship cardinalities (also called Multiplicities or Cardianalities): 1. One to one 2. One to many 3. Many to many We can understand these with the help of a few simple examples;  One to one: One department has one manager. One to many: One class has many students. Many to many: Many teachers can teach many students. Okay, so we have got an abstract overview of the term " Relational ", now the next thing is " Data ", data covers everything, anything... And finally, " Model " means something in the form of a template, design, a kind of blueprint.  To store

Data Modeling

source: A wise person once said a picture is worth a thousand words . In real-world data is not just a few rows of excel sheet, yet it comprises several billion rows expanded through hundreds  of tables. A table is usually made up of rows and columns. Each table represents an Entity . Entity means an Object or thing. That Entity has several properties called Attributes . Those attributes represent the qualities or characteristics of the entity. Since there is more than one entity, so there should be a Relationship between those entities. If we look at the tables we cannot get a clear idea of the relationship between several tables/Entities. Hence, we need to represent the tables/data in the form of a picture or a flow graph. That flow graph or Entity-Relationship diagram is called a Data Model .  Data Modeling is a technique to represent how the tables are related to each other and to represent the structure of da