Here we create the tables on an application startup event.

For production you would probably use a migration script that runs before you start your app. 🤓

/// tip

SQLModel will have migration utilities wrapping Alembic, but for now, you can use <a href="https://alembic.sqlalchemy.org/en/latest/" class="external-link" target="_blank">Alembic</a> directly.

///

Of course, there are some cases where there's no problem in running the previous steps multiple times, in that case, it's a lot easier to handle.

/// tip

### Migration

Check out the [Pydantic migration guide](https://docs.pydantic.dev/2.0/migration/).

For the things that need changes in your Pydantic models, the Pydantic team built [`bump-pydantic`](https://github.com/pydantic/bump-pydantic).

///

If in your use case there's no problem in running those previous steps **multiple times in parallel** (for example if you are not running database migrations, but just checking if the database is ready yet), then you could also just put them in each container right before starting the main process.

### Single Container { #single-container }