Using a domain-speci?¬?c
modeling language for the task of metamodeling brings the same bene?¬?ts as the use of
DSM in any domain: simplicity, precision, and automation. Languages like UML,
MOF, and ER were intended for other domains, entailing greater effort, loss of
precision, and risk of misunderstanding for the reader. These issues are discussed
further in Section 14.3.1, which looks at what is needed in a metamodeling language.
Before looking at metamodels, we will start with an example model of a simple
order handling system (Fig. A.1).
Domain-Speci?¬?c Modeling: Enabling Full Code Generation, Steven Kelly and Juha-Pekka Tolvanen
Copyright # 2008 John Wiley & Sons, Inc.
411
This diagram describes the ?¬‚ow of data when handling orders and invoices. On the
right of the ?¬?gure, we have labeled some examples of the basic constructs that can be
found in all models, whatever their language.
. A graph is one individual model, often shown as a diagram
. Objects are the main elements of graphs, often shown as boxes or circles
. A relationship connects objects together, often shown as a label over the
connection
. A role connects an object into a relationship, shown as a line and often an
arrow-head
. A property is an attribute characterizing one of the above, often shown as a
label
FIGURE A.
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