This page describes declarative schema management using sqldef and the development of qrev, a dedicated data migration tool. Kanmu transitioned from Alembic to sqldef to handle concurrent schema changes as developers and databases increased. Since declarative schema management excels at managing schema definitions but not one-shot SQL execution, the company created qrev. Unlike traditional migration tools, qrev executes unexecuted SQL files in dictionary order without revision concepts, records execution history to prevent re-execution, and re-executes failed SQLs if the file is modified. The article demonstrates qrev's basic operations including init, plan, apply, and status commands with practical examples.
