🗄️ Database Systems
Master database design, SQL programming, and data management principles. Learn about relational databases, normalization, and modern database technologies.
📚 Core Concepts
SQL Fundamentals
Learn the basics of SQL programming and database queries
Database Design
Design efficient and normalized database schemas
Advanced SQL
Master complex queries and database operations
Performance & Optimization
Optimize database performance and query execution
Transactions & ACID
Ensure data consistency and reliability
NoSQL Databases
Explore non-relational database technologies
🔗 SQL Fundamentals
Basic SQL Commands
SELECT Statement
SELECT column1, column2, ...
FROM table_name
WHERE condition
ORDER BY column1;Purpose: Retrieve data from database tables
INSERT Statement
INSERT INTO table_name (column1, column2, ...)
VALUES (value1, value2, ...);Purpose: Add new records to a table
UPDATE Statement
UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;Purpose: Modify existing records
DELETE Statement
DELETE FROM table_name
WHERE condition;Purpose: Remove records from a table
🏗️ Database Normalization
Normal Forms
First Normal Form (1NF)
Rule: Each table cell should contain a single value, and each record needs to be unique.
- No repeating groups
- Atomic values only
- Primary key defined
Second Normal Form (2NF)
Rule: Must be in 1NF and all non-key attributes must be fully dependent on the primary key.
- No partial dependencies
- All attributes depend on entire primary key
Third Normal Form (3NF)
Rule: Must be in 2NF and no transitive dependencies exist.
- No transitive dependencies
- Non-key attributes don't depend on other non-key attributes
🔍 JOIN Operations
Types of JOINs
INNER JOIN
SELECT A.column1, B.column2
FROM table1 A
INNER JOIN table2 B ON A.id = B.id;Returns only matching records from both tables
LEFT JOIN
SELECT A.column1, B.column2
FROM table1 A
LEFT JOIN table2 B ON A.id = B.id;Returns all records from left table and matching from right
RIGHT JOIN
SELECT A.column1, B.column2
FROM table1 A
RIGHT JOIN table2 B ON A.id = B.id;Returns all records from right table and matching from left
FULL OUTER JOIN
SELECT A.column1, B.column2
FROM table1 A
FULL OUTER JOIN table2 B ON A.id = B.id;Returns all records from both tables
📈 Progress Tracking
SQL Fundamentals
85% CompleteDatabase Design
70% CompleteAdvanced SQL
60% CompletePerformance Optimization
45% Complete🎯 Practice Projects
E-commerce Database
Design a complete e-commerce database with products, customers, orders, and inventory management.
- Product catalog with categories
- Customer management system
- Order processing workflow
- Inventory tracking
Library Management System
Create a database for managing books, members, loans, and library operations.
- Book catalog and categorization
- Member registration and management
- Loan tracking and returns
- Fine calculation system
Social Media Database
Design a database for a social media platform with users, posts, comments, and relationships.
- User profiles and authentication
- Post and comment system
- Friend/follower relationships
- Activity feed generation
"Data is the new oil. It's valuable, but if unrefined it cannot really be used." - Clive Humby