Why SQL is not relational: Ordering, Namelessness, and Name Duplication
- In SQL, columns are ordered and can be referred to positionally
- Relational theory is clear that all attributes are referred to by name
- SQL allows for a query to return two columns with the same name
- SELECT Employee.department_id, Department.department_id ...
- SQL allows for a query to return columns without names
- SELECT SUM(salary) FROM Employee