A system must hold the price of every product sold by the company. Which of the following is the price likely to be?

In data and systems modeling, an entity (or object) represents a principal real-world thing, such as a 'product'. An attribute is a property, quality, or characteristic that describes an entity. The 'price' is a specific piece of information that describes the 'product' entity; it does not exist independently. Therefore, in a system designed to hold product information, the price is fundamentally an attribute of the product entity. This concept is central to both Entity-Relationship Diagrams (ERD) and object-oriented analysis, where classes (like Product) have attributes (like price).

B. An entity: An entity is the principal object itself (the product), not a descriptive property like its price.
C. An object: An object represents the entire concept (the product instance), whereas the price is just one of its characteristics.
D. A use case: A use case defines a system's functional behavior or an interaction with a user, not a static data element.

1. Elmasri

R.

& Navathe

S. B. (2017). Fundamentals of Database Systems (7th ed.). Pearson. In Chapter 7

Section 7.3.1

an attribute is defined as a property that describes an entity. For an EMPLOYEE entity

attributes would include Name

Address

and Salary. This directly parallels Product and Price.

2. Dennis

A.

Wixom

B. H.

& Roth

R. M. (2015). Systems Analysis and Design (6th ed.). John Wiley & Sons. Chapter 7

"Moving into Design

" states

"An attribute is some type of information that is captured about an entity... Attributes are the properties of entities" (p. 214).

3. MIT OpenCourseWare. (2020). 6.830/6.814: Database Systems

Lecture 2: Relational Model. Massachusetts Institute of Technology. The lecture materials explain that in the relational model

relations (tables) represent entities

and the columns of a table represent the attributes of that entity. A 'Products' table would have a 'Price' column. (Available at: https://ocw.mit.edu/courses/6-830-database-systems-fall-2020/)

4. Chen

P. P. (1976). The Entity-Relationship Model—Toward a Unified View of Data. ACM Transactions on Database Systems

1(1)

9–36. https://doi.org/10.1145/320434.320440. This foundational paper defines an entity as a "thing" and an attribute as the information describing it (Section 2.1.2).