🗄️ Database Systems

SQL vs NoSQL: Choosing the right tool for the job

🎯 Warm-up Discussion

Let's explore what you already know about databases:

What do you know about databases? Have you used SQL or NoSQL before?
Tell me about your experience working with databases in projects.
What have you heard about the differences between SQL and NoSQL?
Have you ever faced database performance or scaling issues? What happened?
What database technologies have you worked with? Which ones would you like to learn?

📚 Key Vocabulary & Concepts

Learn these important terms before watching the video:

Schema: A blueprint that defines how data is organized in a database

ACID: Atomicity, Consistency, Isolation, Durability - properties that guarantee reliable database transactions (we'll explore this in depth in a future class!)

Scalability: The ability of a database to handle increased workload or grow in size

Relational database: A database that stores data in tables with predefined relationships (SQL)

Foreign key: A field that links tables together in relational databases

Query: A request for data from a database

Document store: A type of NoSQL database that stores data as documents (like JSON)

Key-value pair: A simple data structure with a unique key and associated value

Immutable ledger: A record that cannot be changed once written

🎥 Listening Exercise

VIDEO: SQL vs NoSQL - The Battle of Databases

Part A: Who Said It? (SQL or NoSQL)

Watch the video and identify whether each statement describes SQL or NoSQL databases:

1. Known for being "the reigning Champion" -

2. Organizes data "like a meticulously organized spreadsheet" -

3. All about handling massive amounts of data that don't fit neatly into rows and columns -

4. Enforces a strict schema, like a blueprint for your data -

5. Designed to handle massive data sets and high traffic applications -

6. Has ACID compliance as one of its strengths -

Part B: Complete the Key Phrases

Listen carefully and fill in the missing words from the video:

1. "Choosing the right database is like picking the right from your toolbox."

2. "SQL is your go-to for applications where data is paramount."

3. "NoSQL flexes its when it comes to scalability and flexibility."

4. "The future is looking more and more like a world."

5. "SQL databases are perfect for applications where data integrity is key, like systems."

📖 Reading: Database Scenarios in Real Projects

Read about four developers choosing databases for their projects:

1. Sarah - Building a Banking Application

"For our new online banking platform, we absolutely needed a database that guarantees data accuracy and consistency. We're handling financial transactions where even a tiny error could be catastrophic. That's why we chose a relational database with full ACID compliance. The strict schema ensures every transaction is recorded properly, and foreign keys maintain the relationships between accounts, users, and transaction history. It's been rock solid for our needs."

2. Marcus - Social Media Startup

"When we launched our social media app, we had no idea how it would grow. User posts, comments, likes, images - the data structure kept evolving as we added features. A rigid schema would have slowed us down massively. We went with a document-based NoSQL database that stores everything as JSON-like documents. Now we can add new fields whenever we want without migrating the entire database. Plus, it scales horizontally across multiple servers as our user base grows."

3. Elena - E-commerce Platform

"Our e-commerce site actually uses both! We have a SQL database for our product inventory, orders, and customer accounts - places where we need strong relationships and data integrity. But for our recommendation engine and user behavior tracking, we use a NoSQL solution. It handles millions of events per day and lets us query patterns quickly. This hybrid approach gives us the best of both worlds."

4. James - Content Management System

"I'm building a CMS for news websites that need to publish articles extremely fast during breaking news. Traditional databases were creating bottlenecks during traffic spikes. We switched to a distributed NoSQL database with built-in caching and replication across multiple regions. Now articles can be served from the nearest server to readers anywhere in the world. The flexibility also means journalists can add custom fields to articles without waiting for database changes."

Match each requirement to the correct developer:

Needed database flexibility because data structure kept changing

Prioritized data accuracy and ACID compliance above everything

Uses a hybrid approach with both SQL and NoSQL

Needed to serve content quickly during traffic spikes from anywhere in the world

Stores user posts and comments as JSON-like documents

Uses foreign keys to maintain relationships between entities

Handles millions of tracking events per day

💬 Speaking Section: Database Systems

Discussion cards for meaningful conversation

Which database would you choose for your project?

💡 Discussion tips:

Describe your project's requirements (scalability, data integrity, flexibility)
Use vocabulary: schema, ACID compliance, relational, document-based
Explain your reasoning: "I would choose... because..."

What surprised you most about SQL vs NoSQL?

💡 Discussion tips:

Reference specific examples from the video or reading
Compare their strengths: "SQL excels at...", "NoSQL is better for..."
Use past tense: "I was surprised that..."

Why are companies adopting a hybrid approach?

💡 Discussion tips:

Think about Elena's e-commerce example using both databases
Discuss trade-offs: "They use SQL for... but NoSQL for..."
Use phrases: "The best of both worlds", "it depends on..."

Have you ever worked with databases in a project?

💡 Discussion tips:

Share your personal experience or hypothetical scenario
Use present perfect: "I've worked with...", "I've never used..."
Describe challenges: data integrity, scalability, schema changes

What role does data integrity play in database choice?

💡 Discussion tips:

Consider Sarah's banking example where accuracy is paramount
Implement vocabulary: ACID properties, foreign keys, consistency
Discuss critical vs flexible systems: financial vs social media

When would choosing the wrong database be catastrophic?

💡 Discussion tips:

Think about high-stakes scenarios: banking, healthcare, aviation
Use conditional: "If you used NoSQL for banking, it could..."
Discuss consequences: data loss, inconsistency, security risks

How does scalability influence database decisions?

💡 Discussion tips:

Reference Marcus's startup with unpredictable growth
Compare vertical vs horizontal scaling
Use phrases: "scales horizontally", "handles millions of events"

What are the trade-offs between rigid and flexible schemas?

💡 Discussion tips:

Discuss stability vs adaptability
Use vocabulary: schema migration, data structure, relationships
Present balanced view: "On one hand... but on the other..."

If you were building a social media app, which database would you use?

💡 Discussion tips:

Apply Marcus's experience with unpredictable data structures
Consider features: posts, comments, likes, media storage
Use conditional: "I would use... because..."

What is ACID compliance and why does it matter?

💡 Discussion tips:

Explain Atomicity, Consistency, Isolation, Durability (preview for next class)
Connect to data integrity in critical applications
Use examples: banking transactions, inventory management

🎯 Conversation Starters:

"Based on the video, I think the key difference is..."
"In my experience with databases..."
"If I had to choose between SQL and NoSQL, I'd pick..."
"The hybrid approach makes sense because..."

💡 Remember to use the database vocabulary from today's lesson: schema, ACID compliance, scalability, data integrity, foreign keys, hybrid approach!