The correct first action is to modify the ETL mapping for data types. This is because the log indicates a data type mismatch during ETL processing, specifically a date field being read as a string, which can cause data loss or corruption if not addressed at the transformation layer. By adjusting the mapping to properly cast or convert the source string to the target date format, you align with standard data acquisition best practices—fixing the transformation logic before rejecting or altering the source data. On the CompTIA Data+ DA0-001 exam, this scenario tests your understanding of ETL troubleshooting, where a common trap is to immediately reject the source data or change the source schema, rather than correcting the mapping. Remember the memory tip: “Map it, don’t scrap it”—always adjust the transformation mapping first to handle source anomalies.
DA0-001 Mining and Acquiring Data Practice Question
This DA0-001 practice question tests your understanding of mining and acquiring data. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
Refer to the exhibit.
```
INFO: Starting extraction from source 'SalesDB'
INFO: Connected successfully.
WARN: Data type mismatch in column 'Price': expected NUMERIC, found VARCHAR
ERROR: Row 1523: failed to parse date '2024-02-30'
INFO: Extraction completed with 1 warning and 1 error.
```
Refer to the exhibit. An analyst sees this log during data acquisition. What action should be taken first?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "first"
Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Refer to the exhibit.
```
INFO: Starting extraction from source 'SalesDB'
INFO: Connected successfully.
WARN: Data type mismatch in column 'Price': expected NUMERIC, found VARCHAR
ERROR: Row 1523: failed to parse date '2024-02-30'
INFO: Extraction completed with 1 warning and 1 error.
```
A
Modify the ETL mapping for data types
Adjusting the mapping resolves the type mismatch for all rows.
B
Reject the entire dataset
Why wrong: Rejecting the dataset is drastic; the issues are fixable.
C
Ignore warnings and continue
Why wrong: Ignoring warnings may lead to further data quality issues.
D
Correct the date string in the source
Why wrong: Fixing a single row does not address the systematic type mismatch.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Modify the ETL mapping for data types
The log shows a data type mismatch during ETL (Extract, Transform, Load) processing, where a date field is being read as a string. The correct first action is to modify the ETL mapping for data types to ensure the date string is properly cast or converted to the target date format, preventing data loss or corruption. This aligns with standard data acquisition best practices: adjust the transformation layer to handle source data anomalies before rejecting or altering the source.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Modify the ETL mapping for data types
Why this is correct
Adjusting the mapping resolves the type mismatch for all rows.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Reject the entire dataset
Why it's wrong here
Rejecting the dataset is drastic; the issues are fixable.
✗
Ignore warnings and continue
Why it's wrong here
Ignoring warnings may lead to further data quality issues.
✗
Correct the date string in the source
Why it's wrong here
Fixing a single row does not address the systematic type mismatch.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the misconception that you should always fix the source data first, but in data acquisition, the ETL layer is the standard place to handle format conversions without altering the original source.
Detailed technical explanation
How to think about this question
In ETL pipelines, data type mismatches often arise when source systems store dates as strings (e.g., '2023-01-15') and the target schema expects a DATE or TIMESTAMP type. Modifying the ETL mapping typically involves using a CAST or CONVERT function (e.g., TO_DATE() in SQL or a transformation step in tools like Informatica or Talend) to parse the string into the correct data type. A real-world scenario is ingesting CSV logs where date columns are quoted; failing to map them correctly can cause silent truncation or NULL values, leading to inaccurate reporting.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the DA0-001 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Mining and Acquiring Data — This question tests Mining and Acquiring Data — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Modify the ETL mapping for data types — The log shows a data type mismatch during ETL (Extract, Transform, Load) processing, where a date field is being read as a string. The correct first action is to modify the ETL mapping for data types to ensure the date string is properly cast or converted to the target date format, preventing data loss or corruption. This aligns with standard data acquisition best practices: adjust the transformation layer to handle source data anomalies before rejecting or altering the source.
What should I do if I get this DA0-001 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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