A data analyst is reviewing the error log from a nightly batch load. What is the most likely cause of the error?
Exhibit
Refer to the exhibit. Error log from a data pipeline: [2025-03-15 10:32:14] ERROR: Duplicate key value violates unique constraint 'order_pkey' [2025-03-15 10:32:14] Detail: Key (order_id)=(12345) already exists. [2025-03-15 10:32:15] WARNING: Batch load incomplete. 4999 of 5000 rows inserted.
Trap 1: The data type of order_id is incorrect.
No type conversion error.
Trap 2: The source and target schemas are mismatched.
No schema mismatch error is shown.
Trap 3: The order_id field contains null values.
No null violation error.
- A
A row with the same primary key was already loaded in a previous batch.
The error explicitly says duplicate key.
- B
The data type of order_id is incorrect.
Why wrong: No type conversion error.
- C
The source and target schemas are mismatched.
Why wrong: No schema mismatch error is shown.
- D
The order_id field contains null values.
Why wrong: No null violation error.