Editing Entity–relationship model (section)

== In semantic modeling ==

=== Semantic model ===
A semantic model is a model of concepts and is sometimes called a "platform independent model". It is an intensional model. At least since [[Rudolf Carnap|Carnap]], it is well known that:<ref>{{Cite web|url=https://www.researchgate.net/publication/249853469|title=The Role of Intensional and Extensional Interpretation in Semantic Representations }}</ref> 
:''"...the full meaning of a concept is constituted by two aspects, its intension and its extension. The first part comprises the embedding of a concept in the world of concepts as a whole, i.e. the totality of all relations to other concepts. The second part establishes the referential meaning of the concept, i.e. its counterpart in the real or in a possible world".''

=== Extension model ===
An extensional model is one that maps to the elements of a particular methodology or technology, and is thus a "platform specific model". The UML specification explicitly states that associations in class models are extensional and this is in fact self-evident by considering the extensive array of additional "adornments" provided by the specification over and above those provided by any of the prior candidate "semantic modelling languages".[http://www.tdan.com/view-articles/8589 "UML as a Data Modeling Notation, Part 2"]

=== Entity–relationship origins ===
Peter Chen, the father of ER modeling said in his seminal paper:
: "''The entity-relationship model adopts the more natural view that the real world consists of entities and relationships. It incorporates some of the important semantic information about the real world.''" <ref name=Chen />

In his original 1976 article Chen explicitly contrasts entity–relationship diagrams with record modelling techniques:
:"''The [[Bachman diagram|data structure diagram]] is a representation of the organization of records and is not an exact representation of entities and relationships.''"

Several other authors also support Chen's program:<ref>Kent in [http://www.bkent.net/Doc/darxrp.htm "Data and Reality"] : 
: "One thing we ought to have clear in our minds at the outset of a modelling endeavour is whether we are intent on describing a portion of "reality" (some human enterprise) or a data processing activity."</ref>
<ref>[[Jean-Raymond Abrial|Abrial]] in "Data Semantics" : "... the so called "logical" definition and manipulation of data are still influenced (sometimes unconsciously) by the "physical" storage and retrieval mechanisms currently available on computer systems."</ref>
<ref>Stamper: "They pretend to describe entity types, but the vocabulary is from data processing: fields, data items, values. Naming rules don't reflect the conventions we use for naming people and things; they reflect instead techniques for locating records in files."</ref>
<ref>In [[Jackson Structured Programming|Jackson's]] words: "The developer begins by creating a model of the reality with which the system is concerned, the reality that furnishes its [the system's] subject matter ..."</ref>
<ref>Elmasri, Navathe: "The ER model concepts are designed to be closer to the user’s perception of data and are not meant to describe the way in which data will be stored in the computer."</ref>

==== Philosophical alignment ====
Chen is in accord with philosophical traditions from the time of the Ancient Greek philosophers: [[Plato]] and [[Aristotle]].<ref>Paolo Rocchi, ''Janus-Faced Probability'', Springer, 2014, p. 62.</ref> Plato himself associates knowledge with the apprehension of unchanging [[Theory of forms|Forms]] (namely, archetypes or abstract representations of the many types of things, and properties) and their relationships to one another.