DP-750 Certification Practice Question #38

Question

You are creating a new gold-layer fact table in a Unity Catalog catalog. Requirements:

- ACID transactions with `MERGE`, `UPDATE`, and `DELETE` support.
- Time travel and rollback for accidental data corrections.
- Change data feed so downstream pipelines can read only row-level changes.
- The table must be a **Unity Catalog managed table** that benefits from automatic optimization (predictive optimization, auto-compaction) and the broadest set of platform features.

Which table format should you choose for this managed table?

```sql
CREATE TABLE finance.gold.sales_fact (
  sale_id BIGINT,
  customer_id BIGINT,
  amount DECIMAL(18,2),
  sale_ts TIMESTAMP
)
USING <FORMAT>
TBLPROPERTIES (delta.enableChangeDataFeed = true);
```

Accepted Answer

Only Delta Lake (and Apache Iceberg) can back a Unity Catalog managed table; CSV, JSON, and plain Parquet can only be external, non-transactional tables. Among the listed options, Delta Lake delivers the full requirement set: ACID `MERGE`/`UPDATE`/`DELETE`, time travel and rollback via table history, and change data feed (`delta.enableChangeDataFeed = true`) for row-level incremental consumption — while a managed Delta table also gets predictive optimization and auto-compaction. The `TBLPROPERTIES` clause in the scenario referencing `delta.enableChangeDataFeed` is itself only valid for the Delta format.

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