shancheas
0b0bdd9c4b
- Introduced backend patterns skill with guidelines on API design, database optimization, and server-side best practices. - Added coding standards skill outlining universal coding principles for TypeScript, NestJS, and Node.js development. - Implemented continuous learning skill to automatically extract reusable patterns from Cursor sessions. - Created NestJS best practices skill detailing architecture patterns, dependency injection, error handling, and security measures. - Included various rules and templates for NestJS best practices to ensure production-ready applications.
62 lines
1.6 KiB
Markdown
62 lines
1.6 KiB
Markdown
---
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title: Use Database Migrations
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impact: HIGH
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impactDescription: Enables safe, repeatable database schema changes
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tags: database, migrations, drizzle, schema
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---
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## Use Database Migrations
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Never push schema changes with `drizzle-kit push` in production. Use versioned SQL migrations for all schema changes. Migrations provide version control for your database, enable safe rollbacks, and ensure consistency across all environments.
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**Incorrect (pushing schema or running ad-hoc SQL):**
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```typescript
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// drizzle-kit push against production
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// Mutates the live database with no rollback file
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@Injectable()
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export class DatabaseService {
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async addColumn(): Promise<void> {
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await this.db.execute(sql`ALTER TABLE users ADD COLUMN age INT`);
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}
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}
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```
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**Correct (generate and apply Drizzle migrations):**
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```typescript
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// drizzle.config.ts
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import { defineConfig } from 'drizzle-kit';
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export default defineConfig({
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schema: './drizzle/schema.ts',
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out: './drizzle/migrations',
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dialect: 'postgresql',
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dbCredentials: {
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url: process.env.DATABASE_URL!,
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},
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});
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```
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```bash
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# Generate a migration from schema diffs
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npx drizzle-kit generate
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# Apply migrations
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npx drizzle-kit migrate
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```
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```typescript
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// drizzle/schema.ts
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export const users = pgTable('users', {
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id: uuid('id').primaryKey().defaultRandom(),
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email: varchar('email', { length: 255 }).notNull(),
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age: integer('age').default(0),
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});
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```
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Always keep `down`/rollback SQL when a migration is destructive. Never edit an already-applied migration file; add a new one.
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Reference: [Drizzle Kit Migrations](https://orm.drizzle.team/docs/kit-overview)
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