CodeBlanks Logo Icon CodeBlanks
Login Register

Summary - SQL database

Combine Pool, parameterized queries and transactions to write a sales API.

Summary - SQL database

In this group you learned PostgreSQL and Node.js: the pg module, connection pooling with Pool, security with parameterized queries, integrity with transactions, and ORM with Sequelize.

Raw SQL (pg) gives control; an ORM (Sequelize) gives speed. Small projects often use pg; large ones often use Sequelize. Both rely on parameterized queries and transactions as core tools. Security is never optional: always keep user data separate.

pg vs Sequelize

pg lets you write raw SQL; full control but more code. Sequelize generates SQL for you; less code but less control. The two can be used together.

The choice: pg for small or performance-critical projects; Sequelize for large teams and rapid development. If the ORM falls short on complex queries you can drop to raw SQL with sq.query(). The key point: whichever you pick, use parameterized queries.

Practice Log the type of Pool

Import the Pool class from pg. Log typeof Pool.

Starter code

index.js
// import the module, get the Pool class

// log its type

Sample solution

index.js
const { Pool } = require("pg");
console.log(typeof Pool);

Expected output

function

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 What is the foundation of SQL database security?

  • Network acceleration
  • File compression
  • Updating CSS
  • Parametreli sorgu Correct answer

Explanation: Parameterized queries prevent SQL injection.

2 Match each piece to its role

Term Meaning
pg PostgreSQL client
Pool Connection pool
parameterized query Security
Sequelize ORM

All lessons in Advanced

1 Clustering

  1. cluster module
  2. cluster.fork
  3. Worker IPC
  4. cluster.isMaster
  5. Graceful reload
  6. Summary - Clustering

2 Worker threads

  1. worker_threads
  2. Worker
  3. postMessage
  4. MessageChannel
  5. SharedArrayBuffer
  6. Summary - Worker threads

3 Performance

  1. perf_hooks
  2. Event loop latency
  3. Memory usage
  4. CPU profiling
  5. Optimization
  6. Summary - Performance

4 Security

  1. Helmet
  2. CORS
  3. Rate limiting
  4. Input validation
  5. JWT
  6. Summary - Security

5 MongoDB

  1. Mongoose
  2. Schema
  3. Model
  4. Query
  5. Aggregate
  6. Summary - MongoDB

6 SQL database

  1. pg module
  2. Pool
  3. Parameterized query
  4. Transactions
  5. Sequelize
  6. Summary - SQL database

7 WebSocket

  1. ws module
  2. WebSocket server
  3. Connection
  4. Message
  5. Broadcast
  6. Summary - WebSocket

8 Realtime

  1. Socket.io
  2. io.on
  3. emit and on
  4. Rooms
  5. Namespaces
  6. Summary - Realtime

9 Microservice basics

  1. What are microservices?
  2. Service communication
  3. API gateway
  4. Service discovery
  5. Circuit breaker
  6. Summary - Microservices

10 Message queue

  1. What are message queues?
  2. Bull
  3. Producer
  4. Consumer
  5. Retry and backoff
  6. Summary - Message queue

11 Logging

  1. Winston
  2. Log levels
  3. Transports
  4. Structured logging
  5. Pino
  6. Summary - Logging

12 Configuration

  1. dotenv
  2. Environment variables
  3. Config hierarchy
  4. Validation
  5. Secrets management
  6. Summary - Configuration

13 Advanced testing

  1. Integration tests
  2. Supertest
  3. Test database
  4. Coverage
  5. E2E tests
  6. Summary - Advanced testing

14 Advanced final

  1. Project design
  2. Express + DB
  3. WebSocket
  4. Security
  5. Putting it together