How to automate migration (schema and data) for PHP/MySQL application

I have a "Schema" object that I use - but you could do the same without classes..

What you want to do is create a 'db_schema_versions' table:

CREATE TABLE db_schema_versions (
  `table` varchar(255) NOT NULL PRIMARY KEY, 
  `version` INT NOT NULL
)

After your database can track what version # it is on - it can do SQL upgrades automatically.

You should lock your schema table while upgrading schema. This way you wont have two requests at the same moment trying to upgrade your schema.

So - keep track of the version you are upgrading from - build a big switch - something like this:

class SNTrack_Db_Schema extends MW_Db_Schema_Abstract {
  protected $table = "sntrack_db_schema";
  protected $version = 5;

  protected function upgrade($fromVersion) {
    // don't break
    switch($fromVersion) {
      case 0:
        $this->db->query('CREATE TABLE sntrack_inbound_shipment (
            `id` INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
            `from` VARCHAR(255) NOT NULL,
            `date` DATE NOT NULL,
            `invoice` VARCHAR(255) NOT NULL,
            `notes` TEXT
          )');
        $this->setVersion(1);
      case 1:
        $this->db->query('ALTER TABLE sntrack_details ADD `shipment_id` INT');
        $this->db->query('ALTER TABLE sntrack_product ADD `inventory` INT NOT NULL DEFAULT 0');
        $this->db->query('CREATE TABLE sntrack_inventory_shipment (
            `shipment_id` INT NOT NULL,
            `product_id` INT NOT NULL,
            `qty` INT NOT NULL,
            PRIMARY KEY (`shipment_id`, `product_id`)
          )');
        $this->setVersion(2);
...etc

One way you can go about it is to dump the database into a large sql file using mysqldump. Just take that file and source it within the new installation.