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Databricks · DB-DEP · Professional

Databricks Data Engineer Professional — Practice Questions and Mock Exam

Prepare for DB-DEP with original practice questions and clear answer explanations. Ask Alex, your AI tutor, when you need more detail, use your results to identify topics to review, and practice your pacing with timed mock exams.

59Mock exam questions
120minTime limit

Checked against Databricks · August 2026 · Current exam version

About the exam

The Databricks Certified Data Engineer Professional exam validates advanced expertise in building and optimizing production data systems on the Databricks Data Intelligence Platform. It covers writing data-processing code in Python and SQL, data ingestion and transformation, cost and performance optimization, data security and governance, and debugging and deploying pipelines. Candidates must demonstrate proficiency in Delta Lake internals, Unity Catalog governance, and Spark performance tuning.

This certification is designed for experienced data engineers with one or more years building production data pipelines on the Databricks Lakehouse Platform. It demonstrates the ability to design, secure, and operate complex data systems at scale.

Try five DB-DEP questions

Try five practice questions from the app’s current Databricks Certified Data Engineer Professional question bank, with answers and explanations.

Ensuring Data Security and Compliance1 / 5

A data engineer discovers that Unity Catalog audit logs show unauthorized access attempts to a sensitive production table. What steps should be taken to investigate and remediate?

AlexFull explanation from Alex

Security investigation workflow: 1) Detect: alert on failed access attempts to sensitive tables. 2) Investigate: query audit logs for user identity, access patterns, and timing. 3) Assess: was the user's access attempt legitimate (e.g., wrong table name) or suspicious (repeated attempts on PII tables)? 4) Remediate: revoke excessive permissions (principle of least privilege), add monitoring alerts, implement row filters if data needs to be partially accessible. 5) Prevent: tag sensitive tables with classification tags, create data access policies tied to tags. 6) Report: document the incident, actions taken, and policy changes. Ongoing: schedule weekly audit log reviews for anomalous access patterns.

Sourcedocs.databricks.com

Data Transformation, Cleansing, and Quality2 / 5

A data engineer has a Delta table where some columns contain deeply nested structs and arrays. Analysts complain the data is difficult to query. What flattening strategy makes it accessible while preserving data relationships?

AlexFull explanation from Alex

Nested data flattening patterns: 1) Struct: df.select('order_id', 'customer.name', 'customer.email'). SQL: SELECT customer.name FROM orders. 2) Array: df.select('order_id', explode('items').alias('item')). SQL: SELECT EXPLODE(items) FROM orders. 3) Nested array of structs: df.select('order_id', explode('items').alias('item')).select('order_id', 'item.product', 'item.qty'). 4) Map: df.select('order_id', explode('metadata').alias('key', 'value')). 5) Star expansion: df.select('order_id', 'customer.*'). Expands struct to individual columns. 6) Recursive flattening: for deeply nested structures, write a recursive function that walks the schema and generates the select expressions. 7) Considerations: cardinality explosion — EXPLODE on arrays multiplies row count. Use array_size() to estimate expansion. For high-cardinality arrays (100+ elements), consider aggregation before flattening.

Sourcedocs.databricks.com

Data Governance3 / 5

A data engineer needs to implement a solution that allows different business units to manage their own data catalogs independently while sharing a common governance framework. How does Unity Catalog's three-level namespace support this?

AlexFull explanation from Alex

Unity Catalog namespace: 1) Three-level: catalog.schema.table. Catalog: top-level organizational boundary. Schema: logical grouping within a catalog. Table/View/Function: data objects. 2) Catalog strategies: per business unit: finance_catalog, marketing_catalog. Per environment: dev_catalog, staging_catalog, prod_catalog. Per domain: customers_catalog, orders_catalog. Hybrid: prod_finance, prod_marketing, dev_shared. 3) Ownership delegation: catalog owner manages their catalog. Can create schemas, grant permissions. Cannot modify other catalogs. 4) Governance consistency: metastore admin sets: default permissions. Audit log retention. Data classification requirements. These apply across all catalogs. 5) Migration: from Hive metastore: default (single catalog) → migrate to multiple catalogs. SHOW DATABASES → becomes schemas in a catalog. 6) Limits: one metastore per region. Multiple catalogs per metastore. Hundreds of schemas per catalog. Millions of tables per schema.

Sourcedocs.databricks.com

Developing Code for Data Processing using Python and SQL4 / 5

A data engineer is building a PySpark batch job that must apply a complex, row-level scoring calculation written in pure Python to a DataFrame with 200 million rows. The logic cannot be expressed in built-in Spark SQL functions. The engineer wants the lowest serialization overhead and the best performance available in the DataFrame API. Which approach should they choose?

AlexFull explanation from Alex

Standard Python UDFs in Spark serialize data one row at a time across the JVM-Python boundary, which is expensive at scale. Pandas UDFs (also called vectorized UDFs) instead use Apache Arrow to move columnar batches and execute pandas code on Series or DataFrames, amortizing serialization across many rows. They keep work distributed across executors, unlike collect(), and retain Catalyst planning, unlike the RDD API. For custom Python logic that cannot be expressed in native Spark functions, a Pandas UDF is the recommended high-performance choice. Native Spark SQL functions are still preferred when the logic can be expressed with them. Exam tip: when a question pairs 'custom Python logic' with 'best performance' on large data, pick the Pandas/vectorized UDF over a plain Python UDF.

Sourcedocs.databricks.com

Data Sharing and Federation5 / 5

A data engineer is tasked with building a reverse ETL pipeline that pushes aggregated data from the Delta lakehouse back to an operational CRM system via its API. What architecture supports reliable reverse ETL?

AlexFull explanation from Alex

Reverse ETL components: 1) Source query: SELECT customer_id, total_orders, avg_order_value, churn_score FROM gold.customer_360 WHERE updated_at > last_sync_time. 2) Sync tracking: CREATE TABLE sync_status (record_id STRING, target STRING, last_synced TIMESTAMP, status STRING, error_message STRING). 3) API integration: for batch in batches: try: response = crm_api.upsert(batch). update_status(batch, 'synced'). except RateLimitError: sleep(backoff). retry. except APIError as e: update_status(batch, 'failed', str(e)). 4) Idempotency: use upsert API calls (create or update). Re-running syncs the same records without duplicates. 5) Monitoring: alert when sync failure rate exceeds threshold. Dashboard: records synced per run, error rates, latency. 6) Schedule: match the refresh cadence of the gold table. If gold refreshes daily at 6 AM, sync to CRM at 7 AM.

Sourcedocs.databricks.com

318 practice questions

Use the Pass-IT question pool to practice for DB-DEP. Mock exams are set to 59 questions in 120 minutes.

Pool details: DB-DEP

Objectives in the guide27 objectives listed in the official guide

across 10 domains in the official exam guide

Pool size318 questions

= The pool size is equivalent to 5 sets of 59 questions; this does not mean that each mock exam uses a separate set.

Recorded as checked against sources318 of 318

questions recorded as having their answer, options, and explanation checked against official Databricks documentation

What's on the exam

Developing code for data processing is the largest domain at 22%, covering Python project structure for automation bundles, custom UDF development, and building production-ready ETL pipelines with Structured Streaming and Lakeflow's declarative pipeline framework. Cost and performance optimization follows at 13%, testing Liquid Clustering, deletion vectors, and query-profile-driven tuning rather than basic pipeline construction.

Ingestion, transformation, sharing, monitoring, security, governance, debugging, and modeling round out the exam at 5–10% each, testing narrower operational skills: Delta Sharing configuration, PII masking, event-log debugging, and dimensional modeling with Liquid Clustering in place of manual partitioning.

Exam blueprint: DB-DEP

Developing Code for Data Processing using Python and SQL22%

Structure Python projects for automation bundles and write the UDFs they call, build production ETL with Lakeflow pipelines, Autoloader, and Structured Streaming, handle change-data-capture and control-flow logic within them, and cover the result with unit and integration tests.

≈ 26 h
Data Ingestion and Acquisition7%

Ingest a mix of file formats - from Parquet and JSON to Avro - out of sources like pub/sub buses and cloud object stores, and build a single append-only Delta pipeline that handles batch loads alongside live streaming.

≈ 8 h
Data Transformation, Cleansing, and Quality10%

Write performant Spark SQL and PySpark transformations using windowing, joins, and aggregation, and set up a quarantine step that catches bad records before they contaminate a pipeline.

≈ 12 h
Data Sharing and Federation5%

Share data securely between Databricks deployments and external platforms using Delta Sharing, and configure Lakehouse Federation and live data sharing with proper governance across source systems.

≈ 6 h
Monitoring and Alerting10%

Watch pipeline health and resource usage through system tables, the Query Profiler, and Spark UI event logs, then set SQL-based alerts and job notifications to flag data-quality or performance problems automatically.

≈ 12 h
Cost and Performance Optimization13%

See how letting Unity Catalog manage your tables cuts operational overhead, apply Delta techniques like deletion vectors alongside Liquid Clustering to speed things up, and lean on the query profile when hunting down inefficient joins and shuffling.

≈ 16 h
Ensuring Data Security and Compliance10%

Apply data security mechanisms such as ACLs, row filters, column masks, and anonymization techniques to protect confidential data, and implement compliant pipelines that mask PII and purge data according to retention policies.

≈ 12 h
Data Governance7%

Attach descriptions and metadata to enterprise datasets so they're actually discoverable, and understand how permissions cascade through Unity Catalog's inheritance model.

≈ 8 h
Debugging and Deploying10%

Track down pipeline failures using the Spark UI along with cluster logs and system-table diagnostics, then ship the fix through automation bundles wired into a Git-based CI/CD flow.

≈ 12 h
Data Modeling6%

Design large-scale data models on Delta Lake, replace manual partitioning and Z-ordering decisions with Liquid Clustering, and structure dimensional models built for fast, accurate analytical queries.

≈ 7 h

Exam format and question types

The exam draws 59 scored, multiple-choice questions from a 120-minute session, with unscored pilot items possible. Questions run scenario-heavy across performance tuning, security implementation, and pipeline debugging, expecting fluency with Delta Lake internals and Unity Catalog governance rather than surface-level API recall.

Question types: DB-DEP

Multiple Choice100%

Select the single answer that best meets the question’s requirements.

See Databricks for official question-format information. The shares shown describe the Pass-IT practice pool; they do not establish the proportions on the official exam.

Preparing for DB-DEP

The exam is delivered online with a remote proctor or at a test center, offered in English, Japanese, Portuguese (BR), and Korean. The credential holds for two years, and recertifying means passing the current version of the exam.

Preparation and logistics: DB-DEP

Preparation

Illustrative study time70–180 h

illustrative planning range: 70 h with relevant experience to 180 h when starting out; your needs may fall outside this range

LevelProfessional
Recommended backgroundNone required. 1+ years hands-on Databricks experience recommended. Data Engineer Associate certification helpful but not required.

Taking and maintaining the certification

DeliveryOnline proctored or test center
Retake policyNo mandatory waiting period. Retake fee applies.
Certification validity2 years

Recertification required every 2 years by taking the current exam version.

Common pitfalls

Topics to review: DB-DEP

  1. 01Quarantine Pipeline Design

    Not building a dedicated quarantine path for records that fail validation, instead of dropping or silently passing them through, leads to wrong answers on data-quality pipeline questions.

  2. 02Lakehouse Federation

    Confusing Lakehouse Federation, which queries external systems live, with Delta Sharing, which copies or streams data out, leads to wrong answers on data-source integration questions.

  3. 03PII Anonymization vs Masking

    Mixing up column masking, row filtering, and true anonymization or pseudonymization of PII, and skipping the data-purging side of retention compliance, leads to wrong answers on security-and-compliance questions.

  4. 04Permission Inheritance

    Assuming a Unity Catalog grant at the catalog level always overrides a narrower schema- or table-level grant, instead of understanding the actual inheritance model, leads to wrong governance answers.

  5. 05DAB Project Structure

    Not structuring a Python project for modular development and CI/CD integration within Automation Bundles leads to deployment questions that expect a specific, testable code layout.

Frequently asked questions

How long is the Databricks Certified Data Engineer Professional exam?

The Databricks Certified Data Engineer Professional exam has 59 questions and a 120-minute time limit.

Which pitfalls should I review when preparing for Databricks Certified Data Engineer Professional?

Topics to review include Quarantine Pipeline Design, Lakehouse Federation, PII Anonymization vs Masking, Permission Inheritance, DAB Project Structure. Work through examples to check that you understand the distinctions and can explain your answer.

How do you pass the Databricks Data Engineer Professional exam?

Writing code for data processing in Python and SQL is the largest area at 22%, and the questions show you code rather than describing it. The catalog budget is 120 hours and Databricks recommends a year or more of hands-on platform work. The people who struggle are usually the ones who prepared by reading documentation instead of building and breaking pipelines.

How long is the Data Engineer Professional certification valid?

Two years from the pass date. Databricks recertifies by exam, so you take the current version again rather than logging continuing-education credits. There is no grace period built into that, so the resit has to happen before the expiry date.

How is the Data Engineer Professional exam weighted?

Code for data processing leads at 22%, followed by cost and performance optimization at 13%. Transformation and quality, monitoring and alerting, security and compliance, and debugging and deploying each take 10%, with ingestion, governance, modeling and federation making up the rest. It is spread across ten objectives, so the exam samples the whole job rather than one part of it.

Should you take the Data Engineer Associate first?

Databricks calls the associate certification helpful but not required, so the professional exam can be booked directly. The gap between them is real: 80 hours against 120, and recognition questions against code-reading ones. If you have less than a year on the platform, the associate exam is the cheaper way to find out where you stand.

What experience does the Data Engineer Professional assume?

One year or more of hands-on Databricks work, according to Databricks' own recommendation. No certification gates the booking. The catalog budget of 120 hours assumes that experience is already there, so treat it as a floor rather than a total.

How soon can you retake the Data Engineer Professional exam?

Immediately, as far as Databricks policy is concerned: there is no mandatory waiting period. The constraint is your own preparation rather than a cooling-off rule.

One certification, 12 months

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