How does Drizzle handle schema migrations?

Drizzle handles schema migrations through Drizzle Kit, a separate CLI companion tool. Here's how it works:

Migration Management

According to the README, [README.md:L29-L35], Drizzle Kit provides "hassle-free migrations" with the ability to:

• Generate SQL migration files for you
• Apply schema changes directly to the database

Key Features

The repository data shows several important aspects of migration handling:

1. Separation of Concerns: Migrations are handled through a separate import. For example, in PostgreSQL [changelogs/drizzle-orm-pg/0.14.0.md:L1-L9]:

   import { migrate } from 'drizzle-orm-pg/node/migrate';
   

   Similarly for SQLite [changelogs/drizzle-orm-sqlite/0.14.1.md:L1-L9]:

   import { migrate } from 'drizzle-orm-sqlite/better-sqlite3/migrate';
   

2. Configuration: Migrations are configured through drizzle.config.ts files, as shown in multiple changelog examples.

3. Special Cases: For certain databases like Gel, Drizzle takes a different approach. According to [changelogs/drizzle-kit/0.30.5.md:L3-L30], "Drizzle won't support generate, migrate, or push features" for Gel. Instead, you use the Gel CLI to manage schema and migrations, then use drizzle-kit to pull the schema into Drizzle format.

The design keeps Drizzle ORM lightweight while delegating migration management to Drizzle Kit.

FOLLOW_UPS:

• What databases does Drizzle Kit support for migrations?
• How do you configure schema generation with Drizzle Kit?
• What's the Gel dialect and its workflow?