Question

Which of the following notations in an E-R diagram means that the entity is required?

Answer 1

In an E-R diagram, a solid line indicates that an entity is required or mandatory in a relationship.

Step-by-step explanation:

In an E-R diagram, the notation that indicates that an entity is required is a solid line. A solid line indicates a mandatory relationship between entities. It means that one entity is dependent on another and cannot exist without it. For example, in an Employee and Department scenario, if an employee must be assigned to a department, the relationship between the two would be represented by a solid line.