Free Practice Questions for Databricks Databricks-Certified-Data-Engineer-Associate Exam

The small country lookup DataFrame should be broadcast to the executors. A broadcast join copies the small side of the join to each worker, allowing every executor to join its partition of the billion-row events DataFrame locally. This avoids shuffling the very large DataFrame across the network and is effective when one relation is small enough to fit comfortably in executor memory. Broadcasting events_df would be impractical because it contains billions of rows. Caching or persisting both DataFrames can help when data is reused, but neither action by itself changes the join strategy or removes the expensive shuffle. Databricks exposes the PySpark broadcast function specifically to mark a DataFrame as suitable for a broadcast join. Therefore, option D is the correct optimization.

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In Databricks, when creating a table, you can add a comment to columns or the entire table to provide more information about the data it contains. In this case, since it’s organization policy to indicate that the new table includes personally identifiable information (PII), option D is correct. The line of code would be added after defining the table structure and before closing with a semicolon. References: Data Engineer Associate Exam Guide, CREATE TABLE USING (Databricks SQL)

 An external table is a table that is defined in the metastore and points to an existing location in the storage system. When you drop an external table, only the metadata is deleted from the metastore, but the data files are not deleted from the storage system. This is because external tables are meant to be shared by multiple applications and users, and dropping them should not affect the data availability. On the other hand, a managed table is a table that is defined in the metastore and also managed by the metastore. When you drop a managed table, both the metadata and the data files are deleted from the metastore and the storage system, respectively. This is because managed tables are meant to be exclusive to the application or user that created them, and dropping them should free up the storage space. Therefore, the correct answer is C, because the table was external and only the metadata was deleted when the table was dropped. References: Databricks Documentation - Managed and External Tables, Databricks Documentation - Drop Table

Option C extracts each JSON field into a separate Silver-table column and casts age to the appropriate integer type. get_json_object accepts a JSON string and a JSONPath expression rooted at $; paths such as $.user_id and $.age therefore identify the required top-level fields correctly. This produces analytics-ready columns and prevents downstream queries from repeatedly parsing the original JSON string. Option A returns one nested struct and incorrectly defines age as STRING, so further projection or casting would still be required. Option B attempts field notation directly on a STRING column, which is not valid until the JSON has been parsed into a structured type. Option D omits the required $ JSONPath root and leaves age uncast. Therefore, option C most completely standardizes the source data for the Silver layer.

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https://community.databricks.com/t5/data-engineering/sequential-vs-concurrency-optimization-questions-from-query/td-p/36696

This question’s options do not include the most precise Unity Catalog answer, which would normally be the MANAGE privilege on the schema, because Databricks documents that MANAGE allows a principal to grant and revoke privileges on an object without automatically granting all data-access privileges on that object. However, since MANAGE is not one of the answer choices, the best available answer is D, Schema Owner . Databricks states that schema owners can grant and revoke permissions on the schema, and schema-level administration is a documented responsibility of the schema owner. Option A is incorrect because USE CATALOG and USE SCHEMA only allow object access/navigation and do not confer privilege-management rights. Option B is too broad because a catalog owner governs the entire catalog scope, not just one schema. Option C is too narrow because a table owner controls only one table, not various objects across a schema. So, among the choices provided, Schema Owner is the closest Databricks-aligned answer, though the cleanest real-world implementation would be MANAGE on the schema .

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