Drizzle Migration Workflow After Schema Conversion

Migration Workflow with Drizzle Kit

After converting your SQL to a Drizzle schema, the next step is setting up Drizzle Kit for migrations. Drizzle Kit is the CLI companion to Drizzle ORM that handles schema migrations.

Project Setup

First, install the necessary packages:

npm install drizzle-orm
npm install -D drizzle-kit

drizzle.config.ts

Create a configuration file at the project root:

import { defineConfig } from "drizzle-kit";

export default defineConfig({
  schema: "./src/db/schema.ts",
  out: "./drizzle",
  dialect: "postgresql", // or "mysql" or "sqlite"
  dbCredentials: {
    url: process.env.DATABASE_URL!,
  },
});

Two Migration Strategies

Drizzle Kit offers two approaches:

1. drizzle-kit push (Development)

Pushes schema changes directly to the database without generating SQL migration files. Ideal for rapid prototyping:

npx drizzle-kit push

This compares your TypeScript schema with the live database and applies changes directly. No migration files are created.

2. drizzle-kit generate + drizzle-kit migrate (Production)

Generates SQL migration files that can be reviewed and version-controlled:

npx drizzle-kit generate  # Creates SQL migration files
npx drizzle-kit migrate   # Runs pending migrations

Recommended Workflow

1. Convert SQL to Drizzle using this tool
2. Save the schema to src/db/schema.ts
3. Use push during development for quick iteration
4. Switch to generate before deploying to staging/production
5. Review generated SQL migration files before running them
6. Commit migration files to version control

Schema Organization

For larger projects, split your schema across multiple files:

src/db/
  schema/
    users.ts
    posts.ts
    comments.ts
  index.ts  # re-exports all tables

In drizzle.config.ts, use a glob pattern:

schema: "./src/db/schema/*.ts",

Introspect Existing Database

If you prefer to generate the Drizzle schema directly from a live database instead of converting SQL:

npx drizzle-kit introspect

This connects to your database, reads the schema, and generates Drizzle TypeScript files. The SQL converter tool is useful when you have SQL files but not a running database instance.

Handling Edge Cases

After conversion, review the generated schema for:

• ENUM types that need manual pgEnum() definitions
• Partial indexes that require raw SQL in migrations
• Triggers and functions that are beyond Drizzle's schema scope
• Column comments that need to be added manually