/**
* Reverts a series of SQL patches by looking up their down_sql code and executing it.
*/
public function rollback()
{
$this->logger->log('Database rollback: ' . implode(', ', $this->sql_revert_patches), LOG_DEBUG);
if (!count($this->sql_revert_patches)) {
return;
}
foreach ($this->sql_revert_patches as $patch_name) {
// get the code to revert the patch
$result = $this->driver->query("\n SELECT id, down_sql\n FROM db_patches\n WHERE patch_name = '" . $this->driver->escape($patch_name) . "'\n ORDER BY applied_at DESC, id DESC;\n ");
if (!($patch_info = $this->driver->fetchAssoc($result))) {
return;
}
if ($patch_info['down_sql'] != '') {
// mark the patch as being reverted
$this->driver->query("\n UPDATE db_patches\n SET reverted_at = '" . $this->driver->escape($this->timestamp) . "'\n WHERE patch_timestamp = '" . $this->driver->escape($patch_name) . "';\n ");
// revert the patch
$this->driver->startTransaction();
$this->driver->multiQuery($patch_info['down_sql']);
if (false === $result) {
throw new DatabaseException('Error reverting patch ' . $patch_name . ': ' . $this->driver->getLastError(), 1);
}
$this->driver->doCommit();
}
// remove the patch from the db_patches table
$this->driver->query("\n DELETE FROM db_patches\n WHERE id = " . $this->driver->escape($patch_info['id']) . ";\n ");
$this->logger->log("Patch '{$patch_name}' reverted.");
}
}
