Data, Databases, DBMS and SQL: Understanding the Basics

When we hear the word data, a very familiar definition comes into our mind: Data is the collection of raw information.

Anything which gives us some knowledge about a person, place, thing or event can be considered data.

For example:

An elephant has a long trunk and big ears.
A customer bought a product for ₹25,000.
A student scored 85 marks in mathematics.

All these statements are giving us some information. That information is data.

Now imagine I tell you that I have a red car. It is very easy for you to remember.

Even if I give you information about 10 people, you may still be able to manage it.

But what if there are 1,000 people?

Or 1 lakh?

Or millions of customers?

Now think about companies like Amazon, Google or Facebook.

Every day, millions of people are searching, buying products, making payments, watching videos, clicking advertisements, posting pictures and doing many other activities.

All these activities generate data.

For example, when you place an order on an e-commerce website, the company may store information such as:

Your name
Product purchased
Product price
Date of purchase
Payment method
Delivery address
Order status

And this is just one order.

Now imagine millions of orders every day.

So the obvious question is: Where is all this data stored?

This is where databases come into the picture.

What is a Database?

A database is simply an organized collection of data.

Suppose I run a small electric cycle business and I have only three customers.

I can store the information like this

Customer ID	Name	City
101	Meena	Delhi
102	Rahul	Mumbai
103	Ananya	Pune

For three customers, this looks very simple. I can even maintain this information in Excel.

But now imagine the business grows and I have 5 lakh customers.

Every customer may have

Personal details
Orders
Payments
Service records
Complaints
Delivery information

Now Excel will not be the best way to manage everything.We need a proper system where data can be stored safely and can also be accessed whenever required.That is one of the main purposes of a database.

In the modern world, databases are almost like the backbone of an organization.If a company's important database gets corrupted or becomes unavailable, it can create serious problems.

Imagine an e-commerce company suddenly losing access to all its customer orders.

Who ordered what?
Who has already paid?
Which product has been shipped?
Where should it be delivered?

Everything can come to a stop. This is why data has become such an important asset for businesses.

You may have also heard the phrase:

“Data is the new oil.”

This phrase is coined by a British mathematician and data science entrepreneur Clive Humby. Oil in its raw form is not as useful as it becomes after processing and refining. Data is somewhat similar.

A company may have huge amounts of data, but simply storing data does not automatically create value. Someone has to study it. Someone has to ask the right questions. Someone has to find patterns in it.

This is where Data Analysts come in.

For example, a Data Analyst may use company data to answer questions like:

Why did sales decrease this month?
Which product is selling the most?
Which city generates the highest revenue?

So data is useful, but the real value comes when we are able to extract meaningful information from it.

Then What is a DBMS?

If a database stores the data, then what exactly is a DBMS?

DBMS stands for: Database Management System

A DBMS is software which helps us create, store, manage, retrieve and update data inside a database.

Let us make it simple.

Imagine a celebrity.

A celebrity may have a lot of information and assets associated with them. Schedules, contracts, meetings, interviews, events and so on. Celebrities don't directly manage all of these things. There is usually a manager who handles everything.

I like to think about databases in a similar way.

Database = where the information is stored

DBMS = the manager which helps us manage that information

So if we need some information from the database, the DBMS helps us access it. If we want to add new information, the DBMS helps us do that. If we want to update something, again, the DBMS manages it.

Different Types of Databases

Data is organized into different categories, sometimes into rows and columns, sometimes it may contain documents, images and videos. Because of this, different types of databases are used for different purposes.

1. Relational Databases

Relational databases are most commonly used for data analysis. Here the data is stored mainly in tables containing rows and columns.

For example:

Product	Price	Category
Electric Cycle	25000	EV
Helmet	1500	Accessories
Charger	2000	Electronics

Examples of relational database systems include:

PostgreSQL
MySQL
Oracle Database
Microsoft SQL Server

2. NoSQL Databases

Here, the data is unstructured like images, documents and videos it does not fit neatly into tables.

MongoDB is a popular example.

3. Column-Oriented Databases

Data is stored in columns and are very useful for analytics. Examples include platforms such as:

Google Big Query
Amazon Redshift

4.Graph Databases

Graph databases are useful when relationships between different things are very important. Think about a social media network.

Rahul follows Neha. Neha follows Aman. Aman works at Company X.

The relationship between these people is an important part of the data.

Graph databases are useful for things like:

Social networks
Recommendation systems
Fraud detection

Examples include:

Neo4j
Amazon Neptune

5.Key-Value Databases

Key-value databases are quite simple to understand.

They store information as: Key → Value

For example:

customer_101 → Meena
customer_102 → Rahul
customer_103 → Ananya

You provide the key and get the corresponding value.

Redis and Amazon DynamoDB are popular examples.

Okay, But Where Does SQL Come In?

We have data. We store this data in databases. A DBMS helps us manage databases. But suppose I am a Data Analyst and I want some information from the database. How do I ask for it? Do I open the database and manually search through millions of rows?

Obviously not. This is where SQL comes into the picture.

SQL stands for: Structured Query Language . SQL is a language mainly used to communicate with relational database management systems.

Let us go back to the celebrity example.

If Database = the information and DBMS = the manager

then SQL = the language used to communicate with the manager

Suppose we have this customer table:

customer_id	name	city
101	Meena	Delhi
102	Rahul	Mumbai
103	Ananya	Delhi

Now I want to know:Which customers are from Delhi?

Instead of manually checking every row, I can ask the database using SQL.

SELECT *
FROM customers
WHERE city = 'Delhi';

And the database may return:

customer_id	name	city
101	Meena	Delhi
103	Ananya	Delhi

We are basically asking questions from our data through SQL

For example:

Which customers are from Delhi?

How many products did we sell?

Which city generated the highest revenue?

These are business questions.

SQL helps us convert these business questions into queries which the database can understand.

And this is also why companies value SQL skills so much

Data, Databases, DBMS and SQL: Understanding the Basics

What is a Database?

Then What is a DBMS?