typeorm-migrations

# TypeORM Migrations Skill

Patterns for managing database migrations with TypeORM.

## Configuration

### Data Source Configuration

```typescript
// data-source.ts
import { DataSource } from 'typeorm'
import { User } from './entities/User'
import { Post } from './entities/Post'

export const AppDataSource = new DataSource({
  type: 'postgres',
  host: process.env.DB_HOST || 'localhost',
  port: parseInt(process.env.DB_PORT || '5432'),
  username: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  database: process.env.DB_NAME,
  entities: [User, Post],
  migrations: ['src/migrations/*.ts'],
  migrationsTableName: 'migrations',
  logging: process.env.NODE_ENV === 'development',
})
```

### CLI Configuration

```javascript
// typeorm.config.js (for CLI)
module.exports = {
  type: 'postgres',
  host: process.env.DB_HOST,
  port: parseInt(process.env.DB_PORT),
  username: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  database: process.env.DB_NAME,
  entities: ['dist/entities/**/*.js'],
  migrations: ['dist/migrations/**/*.js'],
  cli: {
    migrationsDir: 'src/migrations',
  },
}
```

## Creating Migrations

### Generate Migration

```bash
# Generate migration from entity changes
npx typeorm migration:generate -d src/data-source.ts src/migrations/AddUserRole

# Create empty migration
npx typeorm migration:create src/migrations/SeedInitialData
```

### Migration Structure

```typescript
import { MigrationInterface, QueryRunner, Table, TableColumn } from 'typeorm'

export class AddUserRole1700000000000 implements MigrationInterface {
  public async up(queryRunner: QueryRunner): Promise<void> {
    // Migration logic
  }

  public async down(queryRunner: QueryRunner): Promise<void> {
    // Rollback logic
  }
}
```

### Table Operations

```typescript
export class CreateUsersTable1700000000000 implements MigrationInterface {
  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.createTable(
      new Table({
        nam