Concepts
PME uses the term "concept." A concept is a collection of properties. A "property" has an identifier (a key into a map actually) and a value. In the diagram below, a concept is depicted as a box containing simple, colored shapes. Each shape depicts an identifier and its color depicts a value. A green square in one concept and a purple square in another concept represent the same identifier but with different values.
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In the diagram below, the parent-child concept relationship is shown. A child concept inherits the properties of its parent while still being able to either override the value of the parent properties or add additional properties of its own.
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The next diagram is the same as above but with each property further classified.
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PME defines "subjects." Subjects are objects that have exactly one associated concept. Examples are physical tables and business columns. In the diagram below, new objects are introduced. Every concept can have a security parent object. A security parent only contributes a security property--nothing else. Note also the default properties. Default properties are coded into PME and are not true concepts. Finally, a subject is introduced. Notice how the subject wraps the concept, and the concept wraps the properties. You can always ask a subject for its concept and ask the returned concept what its ancestors are.
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The final diagram shows a complete relationship--one where a concept gets its properties from (1) a parent concept, (2) an inherited concept, (3) default properties, and (4) child properties. Let's look at each:
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