Databases
Database Analogies
Collected by Giovanna Guerrini — Lecture Notes
Conceptual modeling
Anything else
helps user understanding ternary (and n-ary) relationships as sets of triples (n-uples)
| Symbol | Concept |
|---|---|
| relationship instance | table |
| entity instance | leg |
An instance of the entity might or might not participate to the relationship A instance of the relationship always requires one instance of each related entity
A ternary relationship is like a three legs table: it cannot stand with just two legs
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A notional machine is a pedagogic device to assist the understanding of some aspect of programs or programming. To something along the lines of A notional machine is a pedagogical tool designed to support the understanding of programs, programming, and other aspects of computing such as databases.
