XMI 1.2 MAILINGLIST Avatar
  1. OMG Issue

XMI12 — How to represent a "null" for a Class-valued Attribute?

  • Key: XMI12-60
  • Legacy Issue Number: 3936
  • Status: open  
  • Source: DSTC ( Stephen Crawley)
  • Summary:

    Suppose that my meta-model has a Class whose Attribute has another Class
    as its value. How do I represent this attribute in an XMI document when
    its value is a null object reference?

    According 9.5.4.2, the document should contain something like this:

    <pkg.cls.attr>
    <pkg.othercls xmi.idref="" />
    </pkg.cls.attr>

    Unfortunately, this doesn't work as the empty string is not legal as an
    IDREF value.

    As far as I can tell the 9.3 EBNF rules (e.g. production 7h) don't even
    consider the case where an Attribute's type is a Class.

  • Reported: XMI 1.1 — Thu, 5 Oct 2000 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:12 GMT