Question

I have an application in PHP/MySQL. I am searching for an automated way upgrading database behind the application.
I don’t need to have the compatibility with older versions once it is upgraded.

I have read jeff’s and K. Scott Allen’s articles on this.

I am still not sure how to implement this for a PHP/MySQL application.

Is there any simple and good process for this?

Answer 1

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