3.1. Elements - Complex data type elements

Complex data types are defined by properties. Data type properties are base types, attributes, references and relationships, but also keys. In contrast to keys, which are defined by type definitions, again, attributes, references, relationships and base types are defined as properties (property definition), which, again, refer to a key.

Most element functions will throw an exception when trying to access non existing elements. In order to avoid exceptions, element counts are provided as well as element check functions (exist).