The SEDRIS Data Representation Model
 
APPENDIX B - Constraints
 
Primitive Summary Item Constraints
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Definition
-  An instance of 
<Primitive Summary Item> shall have a
 drm_class field value
    corresponding to one of the following:
 -  For any <Primitive Summary Item>
 instance B that is a component of another 
<Primitive Summary Item Instance> A, the
 drm_class represented
    by B shall be defined as a formal component of A, and the multiplicity
    of B shall comply with the corresponding component relationship between
    the two classes.
 
-  For any <Primitive Summary Item>
 component S of an <Environment Root>
    instance ER, where the drm_class field corresponds to a class P, then
    the component tree of ER shall contain at least one instance of
    P, either in its <Feature Hierarchy>,
    its <Geometry Hierarchy>,
    or both, such that the component tree of the instance of P conforms
    with the pattern specified by S.
 
-  For any <Primitive Summary Item>
 component S of a <Model> instance
    M, where the drm_class field corresponds to a class P, then the
    component tree of M shall contain at least one instance of
    P, either in its <Feature Model>'s
 <Feature Hierarchy>, its
 <Geometry Model>'s
 <Geometry Hierarchy>, or both, such that
 the component tree of the instance of P conforms with the pattern
    specified by S.
 
Rationale
 A <Primitive Summary Item>
 represents an instance or group of instances
 of a primitive class, possibly together with part of its component tree,
 where the pattern thus described appears in the given scope. Consequently,
 the pattern thus described shall correspond to some valid set of
 relationships.
Example
No Example supplied.
FAQs
- Can an 'empty' <Model> have
 <Primitive Summary Item> components?
 
  No; such summary information indicates the presence of instances
  which by definition are not present in an 'empty'
  <Model>.
 
Prev: Precedence of Attribute Set Index.
Next: Property Characteristic Restrictions.
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Last updated: May 15, 2003
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