olemus
andmemudel andmebaasi abstraktseks kirjeldamiseks,
põhielemendid on olem, atribuut ja seos
=
a high-level data model that is used to define the data elements and their relationships in software development

ülevaateid
https://en.wikipedia.org/wiki/Entity%E2%80%93relationship_model

http://study.com/academy/lesson/what-is-the-entity-relationship-model-diagram-examples.html

https://ssyu.im.ncnu.edu.tw/course/CSDB/chap2.pdf

https://www.lucidchart.com/pages/er-diagrams/c?er=1

http://infolab.stanford.edu/~ullman/fcdb/aut07/slides/er.pdf

https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.94.1541&rep=rep1&type=pdf

vt ka
- Cheni notatsioon
- kontseptuaalne andmemudel