public function driver($driver = null, $config = [])
{
if ($driver === null) {
return $this->_driver;
}
if (is_string($driver)) {
$className = App::className($driver, 'Database/Driver');
if (!$className || !class_exists($className)) {
throw new MissingDriverException(['driver' => $driver]);
}
$driver = new $className($config);
}
if (!$driver->enabled()) {
throw new MissingExtensionException(['driver' => get_class($driver)]);
}
return $this->_driver = $driver;
} /**
* Refresh the protected foreign keys variable.
* All foreign keys are removed from the original constraints.
*
* @return void
*/
protected function _extractForeignKeys(Connection $connection)
{
$dialect = $connection->driver()->schemaDialect();
foreach ($this->_constraints as $name => $attrs) {
if ($attrs['type'] === static::CONSTRAINT_FOREIGN) {
$this->_foreignKeys[$name] = $attrs;
$this->_foreignKeysSql[$name] = $dialect->constraintSql($this, $name);
unset($this->_constraints[$name]);
}
}
}
