Database migrations without downtime: expand, migrate, contract
During every deploy, old and new code share one database. How to change the schema without breaking either: expand, migrate, contract.
MySQL
MySQL runs a large share of web applications. Correct data types, schema changes without long locks, and migrations that keep the site online.
Handling money in software: why floats will eventually cost you
How the Vancouver Stock Exchange lost half its index to a rounding rule, and how to store, round and convert money correctly in any stack.