public function generateRules($table)
    {
        $types = [];
        $lengths = [];
        foreach ($table->columns as $column) {
            if ($column->autoIncrement) {
                continue;
            }
            if (!$column->allowNull && $column->defaultValue === null && !$column->isPrimaryKey) {
                $types['required'][] = $column->name;
            }
            switch ($column->type) {
                case Schema::TYPE_SMALLINT:
                case Schema::TYPE_INTEGER:
                case Schema::TYPE_BIGINT:
                    $types['integer'][] = $column->name;
                    break;
                case Schema::TYPE_BOOLEAN:
                    $types['boolean'][] = $column->name;
                    break;
                case Schema::TYPE_FLOAT:
                case Schema::TYPE_DECIMAL:
                case Schema::TYPE_MONEY:
                    $types['number'][] = $column->name;
                    break;
                case Schema::TYPE_DATE:
                case Schema::TYPE_TIME:
                case Schema::TYPE_DATETIME:
                case Schema::TYPE_TIMESTAMP:
                    if (!in_array($column->name, ['created', 'deleted', 'modified'])) {
                        $types['safe'][] = $column->name;
                    }
                    break;
                default: // strings
                    if ($column->size > 0) {
                        $lengths[$column->size][] = $column->name;
                    } else {
                        $types['string'][] = $column->name;
                    }
            }
        }

        $rules = [];
        foreach ($types as $type => $columns) {
            $rules[] = "[['" . implode("', '", $columns) . "'], '$type']";
        }
        foreach ($lengths as $length => $columns) {
            $rules[] = "[['" . implode("', '", $columns) . "'], 'string', 'max' => $length]";
        }

        return $rules;
    }