Deleting a Database Column Is Riskier Than It Looks

A senior engineer at a well-funded startup once dropped a column from a production database on a Tuesday afternoon. The column stored a legacy flag that hadn&rsquo;t been written to in months. The tests passed. The deploy went smoothly. By Wednesday morning, a background job that nobody had touched in two years was silently failing, producing no errors, just wrong data flowing into invoices that…