Reconciliation Rationale - 2006-09-29-001
Return to Category:Referred Reconciliation Issues
The voter on LB issue # 106 in Lab Issues Table - 2006-09 identifies concerns with the comparison of names in an RMIM diagram, and their subsequent representations in Table Views and Excel Views of the same material within a ballot. The names he discusses are all correct, and are correctly represented according to the naming conventions and rules that HL7 has adopted for V3 static models. A brief explanation follows.
Each association in a serialized static model (HMD) has two named properties of import - an association role name, and the identity (name) of the class on the other end of the association. M&M formally adopted naming conventions in 2001 for assigning the names of such elements in RMIMs. These naming convention, and the underlying formal naming algorithms are described in much greater detail in Naming Rules For HL7 Static Information Models.
The primary concern that this voter expresses arises because the graphic representation used to express HL7 RMIMs highlights different properties in the "arrow classes" (so-called because their iconic shape is that of an arrow) than it does in the "rectangular classes". Each "arrow class" connects exactly two rectangular classes (one on each end of the arrow) in the diagram. Thus, the arrow classes associate their terminal classes. For this reason, the HL7 graphic representations labels the arrow class shapes with the name of the association, which is the role name when traversing from the source class to the end class. (Note that a proper RMIM requires that only one of the two possible traversal directions be unblocked.) For the "arrow classes", the class name of the arrow class itself is not shown on the diagram. For the rectangular classes, however, the class shape is labeled with the name of the class (the so-called clone name).
In the "Table View" of an HMD, each class in the RMIM (both rectangular and arrow) is represented by a "box" labeled with the name of the class. For the "arrow classes", this is the name that is not exposed in the RMIM diagram, while the association name that is exposed appears as an associative property of the rectangular class that is the source of the association. In the Excel View, both names are shown on the same row, with the associative name appearing in the "Element Name" column, and the class name appearing in the "of Message Element Type" column.
