Category Archives: Без рубрики

Idempotence in database changes — interview definition Idempotence means that executing the same database operation multiple times produces the same final state as executing it once. In other words:retrying a DB change is safe and does not corrupt data or … Continue reading →

Flyway ✅ Supported. You can point Flyway at any JDBC URL, so you can run the same migration scripts against multiple databases. Each database keeps its own flyway_schema_history table. You typically run: Or configure multiple datasources in CI/CD. Liquibase ✅ … Continue reading →

That depends on the migration tool you’re using. Here are the most common ones: Flyway Flyway keeps migration history in a table called flyway_schema_history in your database. You can check it by running: Or from CLI: This shows applied, pending, … Continue reading →

Nice one 👍 resetting migrations means “wipe the DB back to empty and re-apply everything from scratch.” How you do it depends on whether you’re in dev/test or prod. 🔹 Flyway Clean (drops everything) Drops all objects (tables, views, etc.) … Continue reading →

skipping a migration is sometimes needed (bad script, applied out-of-band, or not relevant in test). How you do it depends on your tool: 🔹 Flyway Flyway tracks migrations in a table called flyway_schema_history. Options: Mark it as applied (skip execution) … Continue reading →

Testcontainers for integration tests (Java): 2) CI: run migrations as a pipeline step Typical PR check pipeline Start DB service (Compose service or CI “services”). Run migrations (Flyway/Liquibase CLI or Maven/Gradle plugin). Run tests (unit + integration). Optionally validate schema … Continue reading →

⚠️ The Problem Imagine you run your app in multiple containers/replicas (e.g. in Docker Swarm, Kubernetes, or just scaling docker-compose up –scale app=3). If each replica runs database migrations on startup, then: All replicas connect to the database at the … Continue reading →

Yes 👍 — migration tools (like Liquibase, Flyway, or custom SQL migration scripts) can definitely be used with Docker. In fact, containerization is very common for managing schema migrations in modern deployments. Here’s how it usually works: 🔹 Common Ways … Continue reading →

Core idea Treat migrations as a separate, run-once step that runs before (or alongside) the app rollout and is safe to re-run. Use the migration tool’s locking/versioning so only one job changes the schema. Typical patterns Dedicated migration job (recommended)CI … Continue reading →

✅ Short Answer Flyway lets you undo a migration using special undo scripts — but only if you’re using Flyway Teams Edition. In open-source Flyway, undo must be done manually (e.g., with a rollback script or by reverting migrations in … Continue reading →