home-information/docs/dev/DataModel.md

Data Model and Concepts

Entity

• A physical or logical object with associated information.
• Has zero or more attributes.
• May or may not have sensors and controllers (from device integrations).
• May or may not have (hidden) EntityState variables.
• May or may not define other entities as delegates of its state.

EntityState

• The hidden state of the entity/device that is sensed and/or controlled
• A single entity may have zero or more states.

EntityStateDelegation

• An EntityState of an entity may just be a proxy for another entity's state. e.g., A thermometer entity with a temperature state is a proxy for an area that is a room.
• We use the terms 'delegate' and 'principal' for the entities involved in the relation.
• Main use is to have the delegate's visual representation reflect the status of the principal's state.
• May be one-to-one, one-to-many or many-to-one relationship.

Location

• Has an SVG image that defines the visual and coordinate space.
• Has zero or more entities.
• Entities optionally associated with a position.
• Has zero or more collections.
• Collections optionally associated with a position.
• Can dfined one or more locations.

LocationView

• Associated with a Location.
• Can define one or more Location Views for a Location.
• Defines the view a bounding box area and rotation of the location SVG.
• Defines what entities are and are not visible in this views.
• Defines the view context for sensors and controllers (info, control)
• ViewContext = { information, control }

LocationItem

• Used as an abstraction/interface for items that can be associated with a Location.
• Helps define a consistent visual represenation for LocationView.
• Initially, Entity and Collection are the two concrete examples fof an LocationItem

EntityPosition / CollectionPosition

• For entities/collections positioned in a Location an visually appearing as an icon.
• Defines the position, scale and rotation of the icon.

EntityPath / CollectionPath

• For entities/collections positioned in a Location an visually appearing as an open or closed path.

Device (runtime concept, not a DB model)

• An entity with at least one sensor or controller

Sensor

• Provides an observation value of a single entity's state variable.
• Sensors and their states can only be created through integrations (not user editable).

Controller

• Provides an action to affect a single entity state variable.
• Controllers and their states can only be created through integrations (not user editable).

Collection

• Defines a logical connection for a group of one or more entities.
• Some entities in a collection may be unpositioned e.g., tools, appliances and devices are potential examples of unpositioned collections
• Collections may or may not be shown in a Location View (as a path).