Entity Modelling

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Duality Diagram

Thinking abstractly about data and how it is (a) described and (b) presented leads to this diagram with its pleasing symmetry.

Figure 7
Data, its description and its presentation.
  • Schema data is data which describes the structure of data.
  • Presentation data is data which describes the presentation of data.
  • Meta-schema data is schema data which describes schema data.
  • Presentation schema data is schema data which describes presentation data.
  • Meta presentation data is presentation data which presents presentation data.
  • Schema presentation data is presentation data which presents schema data.