This is super easy, actually. Unfortunately people see the relational model starting from a "source of truth" database schema and then know about "(de)normaliz

This is super easy, actually. Unfortunately people see the relational model starting from a "source of truth" database schema and then know about "(de)normalization" in the form of "FORMAL forms". The relational model is ALL about normalize and denormalize relations (aka tables). All ways you can combine, recombine, add, remove, change, extend, ... a relation is doing (de)normalization. It means: Add/remove columns, Add/remove rows. So, `SELECT field FROM table` and `SELECT * FROM table WHERE id=1` are this. --- `FORMAL` forms are just observations on the way the data is "It has duplicated rows?" and their properties are useful to understand similar to how is good to know what is different between a `set` and a `vector` of things. And from this, you see how this is useful to use for modeling you RDBMS ("so, I don't need to duplicate all my customer information, I just can use a "pointer"/id for it!").