Tuple Relational Calculus
Set elements are tuples from relations
'Find employees named John'
{t | EMPLOYEE (t) and t.FNAME = "John"}
- Read as: "The set of all t such that t is an element (member) of the relation EMPLOYEE, and the NAME attribute of t has the value John."
QUEL (Ingres) and to some extent SQL are base on tuple R.C. model