SQL Tutorial Series 1 SQL for beginners

Описание: 1. What is a Database
A database is an organized collection of data stored so it can be easily accessed, managed, and updated.

Key points
Structured storage: Data is arranged in a predictable format.

Efficient retrieval: Databases allow fast searching and filtering.

Data integrity: Ensures accuracy and consistency.

Multi‑user access: Many users can work simultaneously.

Real‑world examples
Banking systems

E‑commerce websites

Hospital patient records

Social media platforms
2. What is SQL vs NoSQL
✅ SQL (Structured Query Language)
Used for relational databases.

Data stored in tables with rows & columns.

Uses schemas (fixed structure).

Best for structured data and complex queries.

✅ NoSQL (Not Only SQL)
Used for non‑relational databases.

Data stored as documents, key‑value pairs, graphs, or wide‑column stores.

Flexible schema.

Best for big data, real‑time apps, and unstructured data.

Comparison
SQL → Structured, reliable, ACID‑compliant

NoSQL → Flexible, scalable, high‑performance
3. Types of Databases (RDBMS, OLAP, OLTP)
✅ RDBMS (Relational Database Management System)
Stores data in tables.

Supports SQL.

Examples: MySQL, PostgreSQL, SQL Server.

Ideal for transactional systems.

✅ OLTP (Online Transaction Processing)
Handles real‑time transactions.

Fast insert/update/delete.

Used in banking, retail, ticket booking.

Focus: Speed & accuracy.

✅ OLAP (Online Analytical Processing)
Used for data analysis & reporting.

Supports complex queries on large datasets.

Used in business intelligence, dashboards.

Focus: Insights & analytics.
4. Installing MySQL / PostgreSQL / SQL Server
✅ MySQL Installation
Download from MySQL official website.

Install MySQL Server + Workbench.

Configure root password.

Test connection.

✅ PostgreSQL Installation
Download from PostgreSQL.org..

Install pgAdmin (GUI tool).

Create a new database.

Run sample queries.

✅ SQL Server Installation
Download SQL Server Developer Edition.

Install SQL Server Management Studio (SSMS).

Connect to local server.

Create tables & run queries.