DA0-002 Data Acquisition and Preparation Practice Question
A data analyst needs to merge two customer tables from different sources. One table uses 'CUST_ID' as the primary key, the other uses 'CustomerID'. To ensure accurate merging, the analyst should first:
⚠ Common exam trap
Test-takers frequently assume deduplication (Option C) is the most critical first step, but without first standardizing the join keys, any deduplication logic would operate on mismatched or incomplete data, leading to incorrect results.
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
✓
Normalize the key column names to a common format
Normalizing key column names to a common format (Option B) is the correct first step because the merge operation requires a consistent join key. Without aligning 'CUST_ID' and 'CustomerID' to a single name and data type, the database or ETL tool will treat them as different columns, resulting in a cross join or an error. This step ensures referential integrity and enables an accurate inner or outer join based on the primary 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.
- ✗
Perform a fuzzy match on names
Why it's wrong here
Fuzzy matching is used when no common key exists, but here the key columns can be mapped directly.
- ✓
Normalize the key column names to a common format
Why this is correct
Standardizing key names allows for accurate merging without data loss.
- ✗
Remove duplicate rows from both tables
Why it's wrong here
Removing duplicates before merging is not the first step; duplicates should be handled after merging if needed.
- ✗
Aggregate data by region
Why it's wrong here
Aggregation is not relevant to merging records by key.
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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.