Cardinality shows the number of instances of an entity associated with another entity participating in a relationship. Depend on the cardinality binary relationship can be further dividing into the following categories:

• One-to-one: An entity in A is related with at most one entity in B, and an entity in B is associated with at most one entity in A.

Example: Relationship between university/college and principal

One college only have at the most one principal and one principal can be assigned to only one college.

Likewise we can define the relationship among Vice Chancellor and university.