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RAN-DBDEA-00012
Ranvier · DBDEA

Exam DBDEA Topics: ingestion Difficulty: medium

A team must load JSON booking updates from a Unity Catalog volume with COPY INTO. The producer occasionally adds new fields, so the files do not all share the same schema, and the team wants new fields to appear in the target table automatically instead of causing failures. The target table has not been created yet. Which approach meets these requirements?

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  1. A. Create the table with an explicit schema listing every column seen so far, so that COPY INTO fails fast whenever a file carries an unexpected field
  2. B. Create an empty table without declaring columns and set the table property 'delta.columnMapping.mode' = 'name' so unmatched JSON fields map automatically
  3. C. Read each day's files with spark.read.json, union them with the existing table, and overwrite the table nightly, because COPY INTO cannot handle differing schemas
  4. D. Create an empty table without declaring columns, then run COPY INTO with 'mergeSchema' = 'true' in FORMAT_OPTIONS and COPY_OPTIONS
Reveal answer

Correct answer: Create an empty table without declaring columns, then run COPY INTO with 'mergeSchema' = 'true' in FORMAT_OPTIONS and COPY_OPTIONS

Reference: https://docs.databricks.com/aws/en/ingestion/cloud-object-storage/copy-into

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Official Answer (D): Create an empty table without declaring columns, then run COPY INTO with 'mergeSchema' = 'true' in FORMAT_OPTIONS and COPY_OPTIONS

Ranvier · DBDEA

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