Note
Access to this page requires authorization. You can try signing in or changing directories.
Access to this page requires authorization. You can try changing directories.
The set of type definitions for a schema form a hierarchical tree with a single root known as the Type Definition Hierarchy. The root of this tree is called the ur-type definition. The ur-type definition is unique because it can be used as a complex type or a simple type, depending on the context of the definition.
Ur-types are unconstrained. They are the base type for all simple and complex types.