The yii2-field-range extension enables you to easily setup ActiveField range fields with Bootstrap styling. You basically can setup two attributes joined together like a single field with combined validation error block.
You may have scenarios, where you want to store a specific array configuration to the database. A classic example could be saving Yii widget configuration to the database and then retrieving it at runtime, with dynamic parameters set. This wiki discusses one of the approaches to do this. Let's consider you have something like the NavBar configuration below to store in the db: