Class Type

Every Data Flow is typed. In the case of an Instance Flow, the type is established by a Class. Thus, a given Instance Flow may only hold instances of a given Class. It may be helfpful to think of the flow as a table whose header is composed from an Identifier of that Class.

In reality, the internal content of an Instance Flow is not visible directly to the user, so there is no point wondering which particular Identifier is being used (if any). That said, you can always readily use the content of an Instance Flow to access all attribute values of some subset of instances defined by its Class.