The data child relation is mostly used in the Prime Radiant. It defines the structure of the waterfall tables, along with other things. When an element is defined as the child of another element, it will be displayed as an additional table below its parent. In the meta-circular implementation of the prime radiant for example, the Field element is a data child of the Data element.
|Data Element||The parent data element|
|Child Component||The component of the child element|
|Child Element||The child element|
|Child Field||The dataref field in the child element referencing the parent|