DA0-002 Data Acquisition and Preparation Practice Question
An e-commerce company is merging customer data from three legacy systems. Two systems use email as unique identifier, but one system allows multiple customers per email. The third uses phone number. To create a unified customer view, the analyst should first:
⚠ Common exam trap
Test-takers frequently assume a single unique identifier (email) can be forced as a primary key, ignoring the real-world data quality issue of non-unique emails, which the question explicitly states.
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
✓
Build a customer matching rule that uses multiple attributes (email, phone, name) with a confidence score
Merging data from systems with different identifier schemas requires a probabilistic matching approach. Using multiple attributes (email, phone, name) with a confidence score allows the analyst to resolve conflicts where email is not unique and phone numbers may be missing or formatted differently, creating a unified customer view without forcing a single key.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Request the IT team to modify the legacy system
Why it's wrong here
Modifying a legacy system does not unify the three sources now, and the analyst cannot reconcile conflicting email and phone identifiers by changing one system. Schema changes suit long-term remediation, not the immediate matching step.
- ✓
Build a customer matching rule that uses multiple attributes (email, phone, name) with a confidence score
Why this is correct
Email alone cannot be the match key because one legacy system permits duplicate customers per email, and phone alone is equally unreliable. A multi-attribute rule with a confidence score resolves this by scoring combined agreement across email, phone and name, letting the analyst merge only above a chosen threshold.
- ✗
Use email as primary key and ignore conflicts
Why it's wrong here
Email cannot serve as a primary key because one source permits multiple customers per email, so duplicates would collapse distinct records and silently lose data. Email works as a key only where uniqueness is guaranteed across every source.
- ✗
Assign new unique IDs and discard existing identifiers
Why it's wrong here
Discarding the email and phone identifiers destroys the only cross-system linkage keys, so records cannot be matched into a unified view. New surrogate IDs are useful as a final output after entity resolution, not as a first step replacing the identifiers that enable matching.
Visual reference
Go deeper
Related to this question
About these practice questions
This DA0-002 question is part of Courseiva's 1,004-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DA0-002 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 DA0-002 exam.