1.3.10. Join types (condition)
- Theta: Ai q Bj
(A from R, B from S) - q is comparison operator
=,<,>,!=,>= - Ai and Bj share the same domain
- Equi: Ai = Bj
- Theta join where q is =
- Natural: Ai and Bj are the same attribute
- in two separate relations (name and domain)
- * denotes natural join
- e.g. EMPNAMES * DEPENDENTS
