protected function _init() {
		parent::_init();

		if (!$this->_connection) {
			throw new ConfigException("The `'connection'` option must be set.");
		}

		if (!$this->_source && !$this->_model) {
			throw new ConfigException("The `'model'` or `'source'` option must be set.");
		}

		$connections = $this->_classes['connections'];
		$db = $connections::get($this->_connection);

		if ($model = $this->_model) {
			$model::config(['meta' => ['connection' => $this->_connection]]);
			$this->_source = $this->_source ? : $model::meta('source');
			$this->_locked = ($this->_locked === null) ? $model::meta('locked') : $this->_locked;
		}

		if ($this->_locked === null) {
			if ($db::enabled('schema')) {
				$this->_locked = true;
			} else {
				$this->_locked = false;
			}
		}

		foreach ($this->_config['alters'] as $mode => $values) {
			foreach ($values as $key => $value) {
				$this->alter($mode, $key, $value);
			}
		}
	}