Avoiding Data Inconsistencies: Understanding Fan Trap in Database Design

What type of trap can occur when you have one entity in two 1:m relationships to other entities which can create an association among other entities that is not expressed in the model?

a.) chasm trap
b.) system trap
c.) design trap
d.) fan trap
Final answer: D

Answer:

A fan trap occurs when one entity is involved in two 1:m relationships with other entities, creating an indirect association that is not properly represented, often leading to data inconsistencies.

Explanation: The trap that can occur when you have one entity in two 1:m (one-to-many) relationships to other entities, which can create an association among other entities not expressed in the model, is known as a fan trap. This situation arises in database design, particularly in entity-relationship modeling, when a model inaccurately represents a real-world situation. A fan trap happens when a model suggests that two entities are connected via another entity, yet there is no direct link or path that defines that relationship, leading to incorrect data retrieval and inconsistencies in reporting. A common example of a fan trap can be found in a business context where one department has many employees and each employee works on many projects. However, the number of hours each employee works on a project is not recorded, creating ambiguity and potentially misleading information when trying to ascertain which department is spending how many hours on specific projects.