karloscodes

karloscodes

karloscodes

karloscodes

karloscodes

karloscodes

karloscodes

karloscodes

sequenceDiagram
    participant John as John
    participant DB as Database
    participant Mary as Mary

    John->>DB: begin_transaction()
    Note over DB: Lock acquired on source & dest accounts

karloscodes

// -----------------------------------------------
// OOP dependency injection (the repository implementation can be switched in runtime)
// -----------------------------------------------
class UserService {
  constructor(userRepository) {
    this.userRepository = userRepository
  }

  create(params) {
    validate(params)

karloscodes

version: '3.3'

services:
 pg:
    image: postgres:10
    volumes:
      - pg_data:/var/lib/postgresql/data
    ports:
      - 5432:5432