Databricks Certified Data Engineer - Associate

Explanation

In the Databricks medallion architecture:

• Bronze tables contain raw, unprocessed data
• Silver tables contain cleaned, validated, and enriched data
• Gold tables contain aggregated data for business intelligence

Analysis of each option:

• Option A & B: These perform aggregations (groupBy and agg) which are typically associated with creating Gold tables from Silver tables, not Bronze to Silver transformations.

• Option C: This query performs data cleaning/enrichment by calculating avgPrice using withColumn(col("sales") / col("units")) and writes to a table named cleanedSales. This represents the typical Bronze to Silver transformation where raw data is cleaned and enriched.

• Option D: This writes to a table named uncleanedSales, indicating it's still in the Bronze stage (raw data).

• Option E: This is an incomplete query and doesn't represent a valid transformation.

The key indicators that Option C represents a Bronze to Silver hop are:

• Data transformation/cleaning (withColumn operation)
• Output table named cleanedSales (suggesting cleaned data)
• append output mode (appropriate for incremental data processing)

Therefore, Option C correctly represents moving from Bronze (raw data) to Silver (cleaned, processed data).