In Part 1 we presented some foundation knowledge with which to debunk misconceptions lurking in the industry's "data modeling" mess that Friesendal has tried to catalog. In Part 2 we applied this knowledge to the first two modeling approaches considered by Friesendal, the E/RM and RDM. We apply it here to other two, OO/UML and "GDM".
Object Orientation and Unified Modeling Language
“A "counter revolution" against the relational movement was attempted in the 90’s. Graphical user interfaces came to dominate and they required advanced programming environments. Functionality like inheritance, sub-typing and instantiation helped programmers combat the complexities of highly interactive user dialogs. The corresponding Data Modeling tool is the Unified Modeling Language ...”
In Part 1 we presented some foundation knowledge with which to debunk misconceptions lurking in the industry's modeling mess that Friesendal has tried to map. We now proceed to apply it to the various industry "data models" considered by Friesendal, and his understanding thereof. In this part, we apply this knowledge to the first two industry "data models" considered by Friesendal -- the E/RM and RDM.
"Entity-Relationship Model"
“One of the first formal attempts at a framework for Data Modeling was the Entity-Relationship data model paradigm proposed [in 1976] by Peter Chen. Notice that in the original Chen-style, the attributes are somewhat independent and the relationships between entities are named and carry cardinalities ("how many" participants in each end of the relationship) ... Attributes are related to their "owner" entity" in what other people called "functional dependencies".”
“... I needed to know what the constituent parts of data models really are. Across the board, all platforms, all models etc. Is there anything similar to atoms and the (chemical) bonds that enables the formation of molecules? My concerns were twofold ... I wanted a simple, DIY-style, metadata repository for storing 3-level data models -- what would the meta model of such a thing look like? -- [where] atomicity is of essence ... I took a tour (again) in the Data Modeling zone, trying to deconstruct the absolutely essential metadata, which data modelers cannot do without.”
--Thomas Friesendal, The Atoms and Molecules of Data Models, Dataversity.com
All data models? 3-level data models? Platforms? Hhhmmmm!
