Data Model

A general framework/language for describing organization of data

Relational Model

SQL is based on the relational model where the data is represented as a collection of tables and then there are also constraints about values on in the tables. These tables more precisely are sets of mathematical relations on collection of domains.

The thing that's nice is that it's a very simple and clean model.

Entity Relationship (ER) Model

ER model is a little bit more expressive. It's arguably a better design tool than working directly with the tables. We'll have a way to translate into the relational model.

ER models are sets of entity and sets of pairings between relationships which might not actually just be parents, but they might be parings or ordered n-tuples of elements of the entity sets.