CSC 181 (Midterm Exam)

It is a particular property that describes the entity.

What does ERD means?

It is a real-world item or concept that exists on its own.

What is the third step involved in creating an ERD?

• Determining all interactions between the entities.

• Identifying and defining the entities.

• Analyzing the nature of interactions/determining the cardinality of the relationships.

• Creating the ERD

It is the association that describes the interaction between entities.

It is the number of instances of one entity that can, or must, be associated with each instance of another entity. In general, there may be one-to-one, one-to-many, or many-to-many relationships.

These are entities that associate the instances of one or more entity types. They also contain attributes that are unique to the relationship between those entity instances.

These are objects or concepts that represent important data.

They exist independently from other entity types. They always possess one or more attributes that uniquely distinguish each occurrence of the entity.

One-to-many is marked as: