It is accepted that tables in relational databases should have a primary key, marked with the PK symbol. Admittedly, it is not required, although its absence will generate many problems in the future, including performance issues. Read more »
The final product of the database model is a properly functioning database. Therefore, when designing a database in a modeling program, you should focus not so much on a nice and legible database model (although this is also important) but on correctly defined fields, indexes or relationships between tables, i. Read more »