Session 1: Start With Pain, Not Definitions
Goal: Understand why Excel fails before learning how databases win
What if two students have the same name?
What if a student changes their phone number?
What if three teachers open the file at once?
What if someone deletes a row accidentally?
Let's make this real. Two students named Rahul Sharma.
Teacher A updates the phone number for the wrong Rahul Sharma.
Now Rahul Sharma #2's parents can't be reached during a medical emergency.
Whose fault is this? The teacher? Excel? The system?
Yellow = Duplication | Red = Invalid | Gray = Missing
Same student repeated in multiple rows, multiple files
Different phone numbers for the same person across sheets
Age = "twenty", Fee = "paid" (text vs. numbers)
No reliable way to say "this is THE Rahul Sharma"
Can't link real-world connections: students ↔ courses ↔ fees
This is the fundamental difference.
Excel is a calculator. A database is an ontology.
When systems grew larger — banks, airlines, universities — files broke.
Databases were invented to protect data from humans
Humans make
mistakes
Databases
enforce rules
We need a system that knows Rahul is Rahul, even when:
What kind of system invents rules that even administrators must follow?
It doesn't just store data.
It stores truth about what data means.
"I'll save whatever you type"
"Duplicate him 5 times, I don't care"
"Delete that row? Okay, gone forever"
"You must tell me what Rahul IS before I'll store him"
"Rahul exists once. Everything else connects to him"
"You can't delete Rahul while he still owes fees"
Excel stores values. Databases store truth.
Excel is fragile. Data is dangerous without rules.
How do we build systems that protect us from ourselves?
Next Session: What Is a Relational Database?