hardMultiple Choice
CISA Practice Question: During a nightly batch job, the above error…
Exhibit
Refer to the exhibit. ``` Error: ORA-00001: unique constraint (FIN.UK_ACCT_TRANS_REF) violated INSERT INTO ACCT_TRANS (TRANS_ID, REF_NUM, AMOUNT, DATE) VALUES (?, ?, ?, ?) Call stack: - com.finance.service.TransactionService.processPayment(TransactionService.java:145) - com.finance.batch.BatchJob.run(BatchJob.java:88) ```
During a nightly batch job, the above error appears in the application logs. The transaction table ACCT_TRANS has a unique constraint on the REF_NUM column. Which of the following is the MOST likely root cause?
⚠ Common exam trap
Many candidates confuse a unique constraint violation with a permissions or schema mismatch error, but the specific error message (unique constraint on REF_NUM) directly points to duplicate data from non-idempotent processing, not structural or privilege issues.
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 batch job is not idempotent and is re-processing previously successful transactions
The unique constraint violation on REF_NUM indicates that the batch job is attempting to insert a row with a REF_NUM value that already exists in the ACCT_TRANS table. This occurs when the job is not idempotent—meaning it does not check for or handle previously processed transactions—and re-processes the same data, leading to duplicate key errors.
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 batch job lacks sufficient privileges to insert into the ACCT_TRANS table
Why it's wrong here
Insufficient privileges yield a permission-denied error, not a constraint violation. This would be the cause when the batch account lacks INSERT rights on ACCT_TRANS, but the unique constraint on REF_NUM indicates duplicate values, not authorisation failure.
- ✗
There is a mismatch between the number of columns in the INSERT statement and the table definition
Why it's wrong here
A column-count mismatch produces a different error about column lists or value counts, not a unique constraint breach. This option fits scenarios where the INSERT statement's structure diverges from the table definition, which is unrelated to duplicate REF_NUM values.
- ✗
The batch job is missing an index on the REF_NUM column
Why it's wrong here
A missing index causes slow lookups, not constraint violations; the error stems from duplicate REF_NUM values breaching the unique constraint. Indexes would be the answer for performance tuning of large batch queries, not for an insert failing on uniqueness.
- ✓
The batch job is not idempotent and is re-processing previously successful transactions
Why this is correct
A unique constraint on REF_NUM rejects duplicate inserts, so the violation arises when the job reruns and reinserts transactions already committed in a prior run. Making the job idempotent, via upserts or processed-transaction tracking, prevents this re-processing.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CISA practice question is part of Courseiva's free ISACA 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 CISA exam.