What is Database-tutorial
Imagine you own a small shop. Every day, customers buy items, and you note down details like their name, product, and payment in a notebook.
At first, it is easy. But as your shop grows, your notebook fills up and suddenly, finding old records, updating prices, or checking stock becomes a nightmare!
This is where a Database comes in.
A database is a structured way to store, organize, and manage data so it can be easily accessed, updated, and analyzed.
In simple words it is a digital notebook that stores information systematically.
Think of it like a Roll Number it helps identify each student uniquely.
Example
Here is a basic SQL command to create the above Student table
It may have multiple tables like:
A Database is an organized collection of data that can be easily accessed, managed, and updated electronically.
Why Do We Need Databases?
Here is why databases are essential in today’s world
- Data Organization: Data is stored in tables, making it easy to find what you need.
- Efficiency: Quick searching, inserting, and updating of data.
- Security: Protects sensitive information using authentication and encryption.
- Multi-user Access: Multiple users can use the same data simultaneously.
- Data Relationships: Helps connect related data, like linking a customer to their orders.
What is Data ?
Data simply means information.
For example
- A person’s name — “Aisha”
- Their age - 25
- Their city - “Delhi”
All of these are pieces of data.
When you combine related data together for example, all information about one person it becomes a record.
Database Structure
Databases organize data in a structured format using:
1. Tables
2. Rows (Records)
3. Columns (Fields)
2. Rows (Records)
3. Columns (Fields)
Let us understand these one by one
1. Tables
A table is collection or rows and columns, it is the main component of a database.
It is just like a sheet in Excel it stores information in rows and columns.
Each table represents one type of information.
For example
- A Students table stores student details
- A Courses table stores information about courses
- A Marks table stores exam results
So, instead of saving everything in one big file, databases use multiple tables to keep things organized.
2. Rows (Records)
Each row in a table represents one complete set of information called a record.
Example
| StudentID | Name | Age | City |
|---|---|---|---|
| 1 | Amit Kumar | 21 | Delhi |
| 2 | Rohit Das | 22 | Mumbai |
| 3 | Neha Verma | 20 | Pune |
Here:
- Each row = one student’s record
- The first row stores all information about Amit Kumar
So, a record = one real-world entity (a student, a customer, a product, etc.)
3. Columns (Fields)
Each column represents a field a specific type of data stored for all records.
In the above table:
- Name column stores student names
- Age column stores their ages
- City column stores where they live
Columns define what kind of information the table holds.
Primary Key
When you have hundreds or thousands of records, you need a way to uniquely identify each one.
That is where the Primary Key comes in.
A Primary Key is a column (or a combination of columns) whose value is unique for every record.
In our table, the column StudentID can be the primary key because no two students will have the same ID.
Student Table
Student Table
| StudentID (Primary Key) | Name | Age | City |
|---|---|---|---|
| 1 | Amit Kumar | 21 | Delhi |
| 2 | Rohit Das | 22 | Mumbai |
| 3 | Neha Verma | 20 | Pune |
Think of it like a Roll Number it helps identify each student uniquely.
We will learn about Foreign Keys later, when we discuss how two tables connect with each other.
Example
Here is a basic SQL command to create the above Student table
CREATE TABLE Students ( StudentID INT PRIMARY KEY, Name VARCHAR(50), Age INT, City VARCHAR(50));Explanation
- CREATE TABLE - creates a new table named Students
- StudentID - stores unique IDs (Primary Key)
- VARCHAR(50) - stores text up to 50 characters
- INT - stores numeric values
This structure helps the database know what type of data each column will store.
Real Life Example
Imagine your college database.
It may have multiple tables like:
| Table Name | Store Information About |
|---|---|
| Students | Student details |
| Courses | Course information |
| Results | Exam marks and grades |
Each of these tables connects through IDs but we will learn those relations further
For now, it is important to visualize how tables, rows, and columns make up the database structure.
Two Minute Drill
- A Database stores and organizes data digitally.
- Data means raw information like names, prices, or locations.
- A Table stores data in rows and columns.
- A Row (Record) is one complete set of related data.
- A Column (Field) defines the type of data stored in a table.
- A Primary Key uniquely identifies each record in a table.
- Databases can contain multiple tables connected through keys (we will explore this next).