Values and Known Values

Value and Known (sometimes we say "Known Value") are both system auto-generated tags for an attribute.

This dual "states" of an attribute is created to handle the dual "sources of truth" related to IoT. Traditionally, software applications only consider data within the system as the single source of truth. In IoT, the application may fail (and often do) to correctly represent the current state of the Things - sitting outside the system.

In TQL, the Value is always updated by CRUD operations using queries. The Known is always updated by the outputs of workflows (part of Action). Interactions with external things is always handled by workflows and hence always update the Known of an attribute.