Participation Constraints

Participation constraint defines how many instances of an entity set can participate with another entity set.

Types of Participation Constraint

There are two types of participation, explained below,

1. Partial Participation

  • Each entity in the entity set (i.e., Entity Set A)  may or may not participate in the relationship is known as partial participation.”
  • Partial participation is represented by a single line between the entity set and the relationship set.
  • Partial participation is also known as optional participation.

2. Total Participation

  • Each entity in the entity set (i.e., Entity A) must participate in at least one relationship instance in that relationship set, known as total participation.
  • Total participation is represented through a double line between the entity set and the relationship set.
  • Total participation is also known as mandatory participation.

Let’s Explain with an example

Here,

  • According to partial participation, some courses may exist for which no enrollments are made.
  • According to Total participation, each student must be enrolled in at least one course.