DA0-002 Data Acquisition and Preparation Practice Question
Exhibit
Refer to the exhibit. ERROR: Data type mismatch for column 'transaction_amount' at row 342. Expected DECIMAL(10,2), received VARCHAR. The source system sends transaction_amount as a string with a currency symbol (e.g., '$123.45').
A data pipeline log shows the above error. Which data transformation should be applied during acquisition?
⚠ Common exam trap
Watch out — candidates often assume CAST in SQL can handle any string-to-number conversion, but CAST strictly requires a valid numeric string and will throw an error for non-numeric characters, making preprocessing essential.
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
✓
Preprocess the string to remove non-numeric characters, then convert to DECIMAL
The error indicates that the pipeline encountered a string with non-numeric characters (e.g., '$1,234.56') when trying to load it into a DECIMAL column. Preprocessing the string to remove non-numeric characters (like currency symbols, commas) before conversion ensures the data is clean and parseable, which is a standard data transformation during acquisition to handle dirty source data.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Skip rows that cause errors
Why it's wrong here
Skipping rows leads to data loss.
- ✓
Preprocess the string to remove non-numeric characters, then convert to DECIMAL
Why this is correct
Removing symbols before conversion ensures successful casting.
- ✗
Use CAST(transaction_amount AS DECIMAL(10,2)) in SQL
Why it's wrong here
CAST will fail because the string contains '$'.
- ✗
Change the target column type to VARCHAR
Why it's wrong here
This avoids the error but loses the ability to perform numeric operations.
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