Component Entities and Fields

Component Entities

A component can contain several component entities. The way these entities are organized determines the default Uniface processing behavior at runtime.

The runtime instance of a component entity is known as an occurrence. For more information, see Occurrences.

Component entities that are created from a template are unique to the component and cannot store data in a database. Such entities are typically used to define controls, or transient data that does not need to be shared with other objects.

Component entities that are created from a modeled entity are known as derived entities. They inherit the definitions, properties, and ProcScript of the modeled entity. This ensures that components that access the same data handle it in a consistent way. However, it is always possible to override specific properties, triggers, and other ProcScript modules by defining them locally in the derived entity. The local definition is the one that is compiled and used in the runtime component.

Component Fields

A component field represents a unit of data in a component entity. Fields can be derived from a modeled field and inherit from it, or they can be defined locally in the component. For more information, see Fields.

The Widget property of a component field determines how the field is represented in the user interface and controls how users can use the data in that field.

Each type of user interface component has its own sets of widgets. Widgets in dynamic server pages are JavaScript-based; widgets in static server pages are HTML controls. Widgets in forms may be Windows controls or Unifields (for character based platforms).

Each widget has properties that are specific both to its type and to the application GUI. These properties can be set in the assignment file (to set default property value), in the Properties Inspector (to define initial property values), and in script (to change property values dynamically at runtime). For more information, see Widgets.