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StreamIsReferencedOnDocument
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.. rubric:: Description


This modelling pattern allows to express that a stream is
referenced on a document.
No information about the type of reference is made - it could be symbolic,
textual or both.
It is assumed that, while parsing the information about the stream from a 
data file, an entity for the underlying document can be found or is created
in a database that contains information about documents.


.. rubric:: Definition


A stream (x1) is referenced on a document (x2).


.. image:: StreamIsReferencedOnDocument.svg


::

    
    StreamIsReferencedOnDocument(x1, x2) <->
        edm:ClassOfStream(x1) &
        ClassOfInformationObject(x2) &
        MMT:ReferenceToClassOfIndividualOnDocument(x1, x2) .
    

.. rubric:: Roles

1. hasStream

2. hasOnDocument

.. rubric:: Restrictions

* Role filler of hasStream must have entity type EdmClassOfStream.

* Role filler of hasOnDocument must have entity type ClassOfInformationObject.

* Role filler of hasStream must be used as the role filler of hasThis with respect to the :doc:`../ThisIsAStream/index` pattern.

* One of:

  * Role filler of hasOnDocument must be a specialization of Document.

  * Role filler of hasOnDocument must be used as the role filler of hasThis with respect to the :doc:`../ThisIsADocument/index` pattern.