SQL DDL Commands (CREATE, ALTER, DROP) Explained with PYQs | Class 12th CS Quick Revision 2026

Welcome back to the Class 12th Computer Science Quick Revision Course for the CBSE 2026 Board Exams! 🚀

In this video, we continue with Unit 3: Database Management System (DBMS). We’ve covered the theoretical blueprint in the previous video; now it’s time to start construction. We are moving from concepts to code with SQL Data Definition Language (DDL).

🎯 Goal: To master the structural commands of SQL (CREATE, ALTER, DROP) so you can define and modify database schemas confidently in your practicals and theory exams.

In this video, we cover:
✅ DDL vs. DML: Understanding the difference between defining structure (DDL) and manipulating data (DML).
✅ The Constructors: How to use CREATE to build Databases and Tables with correct data types.
✅ The Destructors: Using `DROP` to permanently remove tables and databases (and avoiding common mistakes!).
✅ The Swiss Army Knife (ALTER): A complete guide to modifying existing tables:
- Adding new columns.
- Removing (Dropping) columns.
- Modifying data types of columns.
✅ Constraint Management: How to add and remove Primary Keys and Foreign Keys using the ALTER command.

📚 About this Course: This "Quick Revision Series" is designed for CBSE Class 12 Computer Science students who want to cover the entire syllabus efficiently.

We focus on:
• Concept Clarity in minutes.
• Previous Year Questions (PYQs) integration.
• Exam-oriented tips and tricks.

🎓 Don't miss a single topic! Access the full ALL-IN-ONE course here: 👉 https://www.youtube.com/playlist?list=PL0q5KicQjiew0sUoOYPeaKkD3PRgfhX1B

🔔 Next Video: Now that our tables are built, we will learn how to handle the data inside the tables using DML Commands (INSERT, UPDATE, DELETE). 👉 Watch here:

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⏱️ Timestamps:
00:00 - Introduction of DDL commands
02:42 - Data Definition Language
03:17 - The CREATE Command (Database & Table)
05:31 - The DROP Command
06:27 - ALTER Command: adding an attribute
07:29 - ALTER Command: removing an attribute
07:58 - ALTER Command: Managing Primary Keys (Add/Drop)
09:11 - ALTER Command: Adding Foreign Key Constraints
11:00 - ALTER Command: modifying an attribute
12:18 - PYQ 1: Name any two DDL commands (CBSE 2024-25 Compartment)
13:07 - PYQ 2: Alter command to remove a column (CBSE 2024-25 Compartment)
13:41 - PYQ 3: Alter command to add a column (CBSE 2024-25 Compartment)
14:26 - PYQ 4: Identify DDL Command (CBSE 2023-24)
14:50 - PYQ 5: Create command (table/database) (CBSE 2023-24 Compartment)
16:42 - PYQ 6: Alter command to add a column (CBSE 2022-23 Compartment)
17:54 - Summary & End notes

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Видео SQL DDL Commands (CREATE, ALTER, DROP) Explained with PYQs | Class 12th CS Quick Revision 2026 канала CS with Python and SQL