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Answer: The batch will fail, and no data will be written to the dataset.
## Explanation In Delta Live Tables (DLT), constraints with `ON VIOLATION FAIL UPDATE` specify that the pipeline should fail when data violates the constraint. This is the strictest enforcement mode available in DLT. ### Key Points: 1. **`ON VIOLATION FAIL UPDATE`**: This clause indicates that if any rows violate the constraint, the entire update operation (batch) should fail. 2. **Behavior**: When a batch contains data that violates this constraint, the pipeline will stop processing that batch, and no data will be written to the target dataset. 3. **Comparison with other options**: - **DROP ROW**: Would silently drop violating rows - **FAIL UPDATE**: Fails the entire batch when violations are detected - No data is written when the batch fails ### Why other options are incorrect: - **Option B**: Incorrect because with `FAIL UPDATE`, the batch doesn't succeed when violations exist. - **Option C**: Incorrect because this describes logging behavior, not failing the batch. - **Option D**: Incorrect because quarantine tables are not created with `FAIL UPDATE`. - **Option E**: Incorrect because metadata recording happens with other violation policies, not with `FAIL UPDATE`. ### Practical Implication: This enforcement mode ensures data quality by preventing any invalid data from entering the dataset, but requires upstream data validation to prevent pipeline failures.
Author: Keng Suppaseth
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A dataset has been defined using Delta Live Tables and includes an expectations clause: CONSTRAINT valid_timestamp EXPECT (timestamp >"2020-01-01") ON VIOLATION FAIL UPDATE What is the expected behavior when a batch of data containing data that violates these constraints is processed?
A
The batch will fail, and no data will be written to the dataset.
B
The batch will succeed, and only rows that pass the constraint will be written to the dataset.
C
The batch will succeed, and all rows will be written to the dataset, but rows that violate the constraint will be flagged in a separate log.
D
The batch will succeed, and all rows will be written to the dataset, but rows that violate the constraint will be moved to a quarantine table.
E
The batch will succeed, and all rows will be written to the dataset, but the constraint violation will be recorded in the system metadata.