database-migration-helper

# Database Migration Helper

Create and manage database migrations safely with proper rollback support.

## Quick Start

Create migration files with up/down functions, test locally, backup before production, run migrations incrementally.

## Instructions

### Migration Structure

**Basic migration:**
```javascript
// migrations/001_create_users_table.js
exports.up = async (db) => {
  await db.schema.createTable('users', (table) => {
    table.increments('id').primary();
    table.string('email').unique().notNullable();
    table.string('password_hash').notNullable();
    table.timestamps(true, true);
  });
};

exports.down = async (db) => {
  await db.schema.dropTable('users');
};
```

### Creating Tables

**With Knex:**
```javascript
exports.up = async (knex) => {
  await knex.schema.createTable('posts', (table) => {
    table.increments('id').primary();
    table.integer('user_id').unsigned().notNullable();
    table.string('title', 200).notNullable();
    table.text('content');
    table.enum('status', ['draft', 'published', 'archived']).defaultTo('draft');
    table.timestamps(true, true);
    
    // Foreign key
    table.foreign('user_id').references('users.id').onDelete('CASCADE');
    
    // Indexes
    table.index('user_id');
    table.index('status');
  });
};

exports.down = async (knex) => {
  await knex.schema.dropTable('posts');
};
```

**With raw SQL:**
```sql
-- migrations/001_create_users.up.sql
CREATE TABLE users (
    id SERIAL PRIMARY KEY,
    email VARCHAR(255) UNIQUE NOT NULL,
    password_hash VARCHAR(255) NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CREATE INDEX idx_users_email ON users(email);

-- migrations/001_create_users.down.sql
DROP TABLE IF EXISTS users;
```

### Adding Columns

```javascript
exports.up = async (knex) => {
  await knex.schema.table('users', (table) => {
    table.string('phone', 20);
    table.boolean('is_verified').defaultTo(false);
  });
};

ex