FC0-U71 Data and Database Fundamentals Practice Question
A database administrator needs to ensure that every record in the 'Orders' table can be uniquely identified. Which constraint should be applied to the 'OrderID' column?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
PRIMARY KEY
A primary key uniquely identifies each row in a table; it must contain unique values and no NULLs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
PRIMARY KEY
Why this is correct
A primary key ensures each row is uniquely identified.
- ✗
FOREIGN KEY
Why it's wrong here
A foreign key links to a primary key in another table and does not guarantee uniqueness in its own table.
- ✗
UNIQUE constraint
Why it's wrong here
A UNIQUE constraint ensures uniqueness but allows NULLs; a primary key is the standard for row identification.
- ✗
CHECK constraint
Why it's wrong here
A CHECK constraint validates data based on a condition but does not enforce uniqueness.
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Same concept, more angles
1 more way this is tested on FC0-U71
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company needs to store customer orders and ensure that each order is uniquely identified. Which database concept should be used?
easy- A.Constraint
- B.Index
- C.Foreign key
- ✓ D.Primary key
Why D: A primary key uniquely identifies each row in a table, ensuring no duplicates and no null values.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This FC0-U71 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the FC0-U71 exam.