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  1. OMG Issue

SYSML11 — SysML unnecessarily restricts aggregation of datatypes

  • Key: SYSML11-118
  • Legacy Issue Number: 12270
  • Status: closed  
  • Source: Change Vision ( Michael Chonoles)
  • Summary:

    The 6th constraint on blocks is written as follows:

    [6] If the aggregation attribute of a property owned by a SysML block is equal to “composite” or “shared,” then the type of the property must be a block

    This constraint, as written, limits the use of solid or hollow diamond aggregation relationships from a block to "own" only other blocks.

    1) This is not what the original intent was. Apparently it was to prevent the use of aggregation relationships from a block to own dataTypes or valueTypes.
    As written, it is overly restrictive for its intent

    2) Even the intent is overly restrictive. UML modelers have (for years) modeled the relationship between a class and its attributes as an aggregation relationship.True, software developers have occasionally used the distinction between composite/shared as implementation clues which are unimportant to SysML concerns. However, even though the SysML distinction between an association, aggregation, or composition relationship to a property is irrelevant, the variation of notation allows modelers to use the style they are most familiar with. In addition, for models that move from SysML to UML and back, it allows the preservation of the software hints. It also leverages existing training and educational material on models.

    I recommend dropping this constraint completely. At the most, add a sentence in the description section explaining that using the composite/shared relationship to properties has no implementation meaning.

  • Reported: SysML 1.0 — Mon, 10 Mar 2008 04:00 GMT
  • Disposition: Resolved — SysML 1.1
  • Disposition Summary:

    No Data Available

  • Updated: Fri, 6 Mar 2015 20:58 GMT