One to Many Relation on Controls Relationship Type

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In this class, we will understand One to Many Relation on Controls Relationship Type.

We have already discussed the concepts of Many to Many Relation.

Table of Contents

Let’s consider the ER-Diagram as shown below.

In the above diagram, if we consider the controlling department of the project entity type, it relates to the department entity type.

Whenever an attribute of an entity type is referencing another attribute, there exists a relationship.

The image below is the ER-Diagram with controls relationship type.

The requirements state that “A Department controls several projects.”

The maximum participation of the department entity is N.

A project is controlled by only one department.

The maximum participation is 1.

The cardinality ratio of the ‘controls’ relationship is N:1.

The image below is ER-Diagram with cardinality ratios.

For this, we will consider the general logic that some departments will not control projects.

For example, the employee grievance department of a company will not control any project.

The minimum participation is zero, so it has partial participation.

Similarly, every project is under any of the department’s control.

So the projects have full participation in the controls relationship type.

The image below is the ER-Diagram with the controls relationship.