Entity vs. attribute: Is an attribute defined as a person, place, object, or event in the user environment?
-
ACorrect
-
BIncorrect
-
CCorrect only for dimensional models
-
DDepends on the level of normalization
Answer
Correct Answer: Incorrect
Explanation
Introduction / Context:Clear distinction between entities and attributes is foundational to ER modeling. Confusing the two leads to poor schemas and query complexity.
Given Data / Assumptions:
- An entity is a person, place, object, event, or concept about which data is stored (e.g., Customer, Product, Order).
- An attribute is a property that describes an entity (e.g., customer_name, product_price).
- The statement mislabels the definition.
Concept / Approach:The phrase “person, place, object, event” defines an entity, not an attribute. Attributes are characteristics of entities or relationships. Getting this right ensures proper table design: entities typically become tables; attributes become columns; relationships become foreign keys or associative tables.
Step-by-Step Solution:List the nouns central to the business domain—these are candidate entities.For each entity, list descriptive properties—these are attributes.Assign primary keys to entities; define data types and constraints for attributes.Model relationships between entities with appropriate cardinalities.
Verification / Alternative check:Try mapping “Order” to a table (entity) and “order_date” to a column (attribute). If you reverse them, design breaks down quickly.
Why Other Options Are Wrong:Dimensional or normalization level does not change the fundamental definitions.
Common Pitfalls:Promoting an attribute to an entity prematurely (or vice versa); using vague attribute names like “name” without context.
Final Answer:Incorrect