root/trunk/data/migrations/004_m1.php

<?php
class Migration004 extends sfMigration 
{

  // Adding blog table
  public function up() 
  {
    $this->executeSQL("SET FOREIGN_KEY_CHECKS = 0;");
    $this->executeSQL("DROP TABLE IF EXISTS `blog_posts`;");
    $this->executeSQL("CREATE TABLE `blog_posts` (
      `id` INTEGER  NOT NULL AUTO_INCREMENT,
      `title` VARCHAR(255)  NOT NULL,
      `slug` VARCHAR(255)  NOT NULL,
      `body` TEXT,
      `author_id` INTEGER  NOT NULL,
      `is_published` INTEGER default 0 NOT NULL,
      `created_at` DATETIME,
      `updated_at` DATETIME,
      PRIMARY KEY (`id`),
      KEY `blog_posts_is_published_index`(`is_published`),
      KEY `blog_posts_created_at_index`(`created_at`),
      KEY `blog_posts_updated_at_index`(`updated_at`),
      KEY `post_index`(`slug`, `created_at`, `is_published`),
      INDEX `blog_posts_FI_1` (`author_id`),
      CONSTRAINT `blog_posts_FK_1`
        FOREIGN KEY (`author_id`)
        REFERENCES `sf_guard_user` (`id`)
        ON DELETE SET NULL
    )Type=MyISAM;");
    $this->executeSQL("SET FOREIGN_KEY_CHECKS = 1;");
  }

  // Dropping blog table
  public function down() 
  {
    $this->executeSQL("SET FOREIGN_KEY_CHECKS = 0;");
    $this->executeSQL("DROP TABLE IF EXISTS `blog_posts`;");
    $this->executeSQL("SET FOREIGN_KEY_CHECKS = 1;");
  }

}