What is Relation?

$\Delta_1, \Delta_2, ... \Delta_m$ $\Delta_1 \times \Delta_2 \times ... \Delta_m$ is the set of tuples

$\pi \in \Delta_1 \times \Delta_2 \times ... \Delta_m$ → Relation is the subset of Cartesian Product

• $\Delta_1$ : SUPERVISOR - STRINGS
• $\Delta_2$ : STUDENTS - STRINGS
• $\pi$ = {(”E”, “A”), (”N”, ”C”), (”P”, “E”)}

<aside> 💡 A relation in the relation model is a relation where each domain has a unique name

</aside>

Example 1.

Name Relation: Supervisor - Student

• Number of attributes is Grade
• The number of Tuples is the Cardinality
• Supervisor - Student is a relation of Grade 2

Example 2.