migrations: don't try to use transactions on mysql

classes/db/migrations.php

@@ -82,6 +82,8 @@ class Db_Migrations {
 			else
 				Debug::log("Starting migration to $version...", Debug::LOG_VERBOSE);
 
+			// mysql doesn't support transactions for DDL statements
+			if (Config::get(Config::DB_TYPE) != "mysql")
 				$this->pdo->beginTransaction();
 
 			foreach ($this->get_lines($version) as $line) {
@@ -99,7 +101,9 @@ class Db_Migrations {
 			else
 				$this->set_version($version);
 
+			if (Config::get(Config::DB_TYPE) != "mysql")
 				$this->pdo->commit();
+
 			Debug::log("Migration finished, current version: " . $this->get_version(), Debug::LOG_VERBOSE);
 
 		} catch (PDOException $e) {