Why database migration tools' schema builders beat raw SQL for most tasks

Developers using migration tools like Kysely and db-migrate often default to writing raw SQL strings even for simple operations such as adding columns or indexes, despite these tools offering built-in schema builders. Writing raw SQL hardcodes database-specific syntax, meaning migrations can break when switching between engines or running tests on a different database than production. Schema builders abstract away dialect differences, automatically translating generic type definitions into the correct syntax for PostgreSQL, MySQL, or other engines. Raw SQL also makes rollback migrations more error-prone, as developers must manually write a correct reverse operation, a step that is frequently skipped or implemented incorrectly. While raw SQL remains necessary for complex or advanced operations, the schema builder is the safer and more portable default for routine migration tasks.