Understanding Databases and SQL: How It Works

A database is a collection of data organized and stored so that it's easy to access and use.

There are two main types of databases:

1. Non-Relational Database

2. Relational Database

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1. Non-Relational Database

Non-relational databases store data in flexible formats like key-value pairs, documents, or graphs. This means the data doesn't have to follow strict rules about how it's stored.

For example, in a non-relational database, you can store customer information in a container like this:

If you have multiple data, they are stored as:

Non-relational databases are useful when data doesn't fit neatly into tables. However, they can be harder to work with when you need well-organized data.

Therefore, we prefer relational databases when structured data storage is required.

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2. Relational Database

Relational databases store data in tables with rows and columns.

Example: Organizing Customers

If you're managing customers, you can organize them in a table as follows:

Here, data is neatly organized into rows and columns; this is how relational databases operate.

Since the data is stored in a tabular form, we can use SQL (Structured Query Language) to manage and interact with the data.

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What is SQL?

SQL is a tool for working with databases and helps you:

1. Add or change data: For example, update customer information.
2. Find specific data: Find the top-purchasing customers.
3. Organize data: Group customers by age or region.

SQL is powerful and easy to learn, making it a versatile tool for professionals in Data Science, Web Development, and Business Intelligence.

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How does SQL work?

The following key components work together to execute SQL queries:

1. Database

2. SQL Query

3. SQL Query Processing

1. Database

A database is where data is stored and organized in a structured format.

2. SQL Query

We use SQL to store, manipulate, and retrieve data from the databases. The instructions we write for this are called SQL queries.

For example,

SELECT * FROM Customers;

3. SQL Query Processing

When we execute an SQL query, the database engine processes it in three steps:

This approach ensures SQL queries are valid, flexible, and powerful.

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Why does SQL stand out?

1. Easy to Learn

SQL syntax is simple and intuitive.

For example, compare

SELECT CustomerName FROM Customers; 

with plain English—"Select customer names from the customers' table."

2. Versatile Applications

SQL is used in a wide variety of fields like:

• Data Science and Machine Learning
• Web and App Development
• Business Intelligence and Marketing

3. Universal Skill

SQL works with most database systems, handles large datasets, and remains a valuable skill across industries.

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