IPA IP 2021 Question 1

A question IPA Japan published in 令和3年度 ITパスポート試験公開問題問1, translated into English. ITPEC is based on the same exams.

Which of the following is an appropriate reason for performing data modeling by using an E-R diagram?

a)To understand the exchange of data in business operations, and clarify the workflow.b)To understand the flow of data in the current business operations, and clarify the problems in carrying out the business operations.c)To illustrate the relationships between the objects managed in business operations, such as customers and products, and clarify their meaning in the business operations.d)To examine the data items in detail, and clarify the method of implementing the database.

Explanation

To show the relationships between business objects such as customers and products, and clarify their business meaning — that is what an E-R diagram is drawn for.

An E-R (Entity-Relationship) diagram models the things a business manages as entities (customer, product, order) with their attributes, and the relationships between them, with cardinalities such as one-to-many: a customer places many orders, an order is for one customer. Drawing it makes the business rules behind the data visible, independent of how the data will later be stored.

Answer (c)

Why not others:

•(a) — showing who exchanges which data in a business and clarifying the workflow is the job of a workflow or business flow diagram
•(b) — tracing how data flows through current operations to find problems is what a DFD (data flow diagram) is used for
•(d) — working out data items in detail and how to implement the database is physical database design, a later step than conceptual data modeling

Key rule: E-R diagram = entities and the relationships between them (the data's structure and meaning); DFD = how data flows and is processed; flowcharts and workflow diagrams = the order of work.

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This question comes from the past questions IPA Japan publishes, translated into English by ITPEC Practice. ITPEC Practice is an independent study tool and is not affiliated with IPA or ITPEC. See the original paper (PDF) or Report an issue.