A Simple Bank

Features

• Create and manage account
  • Owner
  • Balance
  • Currency
• Record all balance changes for each account
  • Create an account entry for each change for each account
• Money transfer transaction
  • Perform money transfer between 2 accounts consistently within a transaction

Pre-requisites

• Install docker for desktop
• Execute brew install golang-migrate sqlc
• Execute go install github.com/golang/mock/mockgen@v1.6.0

Database Design

• Design DB schema using dbdiagram.io
  • Export the queries onto /dbdiagrams.io
• Save and share DB diagram within the team
• Generate SQL code to create database in a target database engine i.e. postgres/MySQL/SQLServer

Docker and Postgres

• Execute docker pull postgres:12-alpine to get the postgres image
• Execute docker run --name postgres12 -p 5432:5432 -e POSTGRES_USER=root -e POSTGRES_PASSWORD=secret -d postgres:12-alpine to run the postgres container
• Execute docker logs postgres12 to see the logs
• Execute docker exec -it postgres12 psql -U root to connect to the postgres container and login as root user
• Connect to postgres container and execute the queries from /dbdiagrams.io to create the tables

DB migration

• Execute migrate -version to verify that the golang-migrate has been installed
• Execute migrate create -ext sql -dir db/migration -seq init_schema to generate migration files
  • *.up.sql is used to migrate up to a new version using migrate up
  • *.down.sql is used to migrate down to an older version using migrate down
  • Copy the sql quesries generated from dbdiagram.io to *.up.sql
  • Add DROP TABLE queries to *.down.sql
• Execute make migrateup to migrate data upwards to a new version
• Execute make migratedown to revert migration to a previous version
• Manage migrations in future with migrtion up/down commands

DB and Docker Setup for development

• Execute make postgres to run postgres container on local docker setup
• Execute make createdb to create the simple_bank database
• Execute make migrateup to setup tables and initial database state
• If required,
  • Execute make dropdb to drop database
  • Execute make migratedown to migrate or revert database state to a previous version

Generate CRUD Golang code from SQL

• Execute make sqlc to auto generate CRUD functionalities
• Execute make mock to generate mock DB