Migration Class

The Migration Class is a way to manage changes to your database schema over time. It provides a structured and versioned way to track and apply changes (such as creating tables, adding columns, or modifying indexes) in code.

This allows you to evolve the database schema in a controlled and reproducible manner.

Enabling and Loading Migration

Like most other classes in LavaLust, the Migration library is initialized in your controller using the $this->call->library() method:

<?php
$this->call->library('migration');

Once loaded, the Migration library object will be available using:

<?php
$this->migration;

You must also enable migrations in the configuration file:

<?php
// File: app/config/migration.php
$config['migration_enabled'] = true;
$config['migration_path'] = 'app/migrations';
$config['migration_table'] = 'migrations';

Controller Example

Create a controller (e.g. Migrations.php) to handle migration commands:

<?php

class Migration extends Controller {

    public function __construct()
    {
        parent::__construct();
        $this->call->library('migration');
    }

    public function create_migration($migration_class)
    {
        // e.g. $migration_class = "create_users_table"
        $this->migration->create_migration($migration_class);
    }

    public function migrate()
    {
        $this->migration->migrate();
    }

    public function rollback()
    {
        $this->migration->rollback();
    }
}

Routes Example

Add routes so you can call these actions via the browser:

<?php
$router->get('create-migration/{migration_class}', 'Migration::create_migration');
$router->get('migrate', 'Migration::migrate');
$router->get('rollback', 'Migration::rollback');

Creating a Migration File

Visit the following URL to create a new migration file:

http://localhost/project_name/create-migration/create_users_table

This will generate a file like app/migrations/001_create_users_table.php.

Open the file and define your schema:

<?php

class Create_users_table {

    private $_lava;
    protected $dbforge;

    public function __construct()
    {
        $this->_lava =& lava_instance();
        $this->_lava->call->dbforge();
    }

    public function up()
    {
        // Define the table structure
        $this->_lava->dbforge->add_field([
            'id' => [
                'type'           => 'INT',
                'constraint'     => 11,
                'auto_increment' => TRUE
            ]
        ]);
        $this->_lava->dbforge->add_key('id', TRUE);
        $this->_lava->dbforge->create_table('your_table_name');
    }

    public function down()
    {
        // Drop the table
        $this->_lava->dbforge->drop_table('your_table_name');
    }
}

Running Migrations

Run all pending migrations

Visit:
```
http://localhost/project_name/migrate
```
Rollback the last migration batch

Visit:
```
http://localhost/project_name/rollback
```

Available Methods Reference

Method	Description
`create_migration($name)`	Creates a new migration file with the given name inside `app/migrations`
`migrate()`	Executes all available migration files that have not been run yet
`rollback()`	Reverts (drops) the most recent migration batch

Note

Each migration file must contain an up() method (to apply changes) and a down() method (to rollback changes).