DA0-002 Data Governance Practice Question
Exhibit
Refer to the exhibit. ERROR: Duplicate entry '12345' for key 'PRIMARY' Query: INSERT INTO customers (customer_id, name, email) VALUES (12345, 'John Doe', 'jdoe@example.com');
Refer to the exhibit. A data analyst receives this error when running a data load script. What is the most likely cause?
⚠ Common exam trap
DA0-002 often tests whether candidates can distinguish between constraint violations (duplicate key, NOT NULL, foreign key) and other error classes like connection loss or data truncation, so the trap is picking a generic 'connection lost' answer instead of reading the specific error code.
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
✓
The customer_id 12345 already exists in the table
The error shown in the exhibit is a duplicate key / unique constraint violation, which occurs when the load script attempts to insert a customer_id value that already exists in the target table. Since customer_id is the primary key (or has a unique constraint), the database rejects the insert with a duplicate entry error. The most likely cause is that customer_id 12345 is already present in the table, so the load must use an upsert, deduplication, or filtered insert strategy.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The email field is too long
Why it's wrong here
The exhibit reports a null/constraint violation on a required column, not a length or truncation fault, so field width is not implicated. Length limits are tempting because oversized values do cause load failures, and this would be correct if the error cited truncation or a maximum-length overflow.
- ✗
The database connection is lost
Why it's wrong here
A dropped connection produces timeout or socket errors, not the constraint violation shown in the exhibit. Connection loss is tempting because load scripts do fail mid-transfer, and it would be correct if the error referenced an unreachable host or closed session rather than a rejected row value.
- ✓
The customer_id 12345 already exists in the table
Why this is correct
The load fails because customer_id 12345 already exists, breaching the primary key or unique constraint on that column. The insert is rejected rather than duplicating the row, confirming a uniqueness violation rather than a datatype or connection fault.
- ✗
The name field is null
Why it's wrong here
The exhibit's error identifies the offending column as the email field, not the name field, so the null sits elsewhere. Null names are tempting because missing required values do break loads, and this would be correct had the error message named the name column as the violated constraint.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
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.