Migrations ensure that changes in the database between updates or during the installation are correctly applied.

The migration system from the core reads all files in the _migrations folders that exist in the modules folder in order. You need to specify the order with incremental prefixes.

├── _migrations/
│   ├── 1_create_test_table.php
│   ├── 2_update_table_with_new_fields.php

This way we can assure that changes can be based on other changes.

The migration file: 🔗

<?php

namespace Migrations;

use Controllers\Panel;
use Migration\MigrationInterface;

class create_test_table extends MigrationInterface {

    public function up() {
        $result = Panel::getDatabase()->custom_query(<<<SQL
            CREATE TABLE `test` (
                `id` int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
            ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ROW_FORMAT=COMPACT;
        SQL);
        return $result;
    }

    public function down() {
        $result = Panel::getDatabase()->custom_query(<<<SQL
            DROP TABLE `test`;
        SQL);
        return $result;
    }

    public function getName() {
        return "create_test_table";
    }
}

As you can see, we extend the MigrationsInterface, which will have the up and down methods. The class name and migration name are the same.

Helpers 🔗

In order to work with the Migrations, we have some helper functions we can call:

MigrationHandler::getInstance()->ensureMigrations(
    ['create_test_table', 'update_table_with_new_fields']
);

checkMigrationStatus / getAppliedMigrations 🔗

get a list of all the applied migrations.

getNewMigrations 🔗

get a list of migrations that have not been applied yet.

applyMigrations 🔗

apply all migrations that have not been applied yet.

loadMigrations 🔗

anotherway to get a list of migrations.

ensureMigrations 🔗

takes an array and return either true of false if all the migrations have already been applied or not.