Pass the Microsoft Certified: Azure Databricks Data Engineer DP-750 Questions and answers with ExamsMirror

The correct answers are B and D. Delta Lake's data retention behaviour is controlled by two distinct properties that work together:

delta.deletedFileRetentionDuration governs how long physically deleted data files are kept before VACUUM can remove them. Setting this to 30 days ensures deleted records remain on storage for the full audit window.

delta.logRetentionDuration controls how long the transaction log is retained. Time-travel queries (SELECT ... VERSION AS OF or TIMESTAMP AS OF) rely on the log to reconstruct historical table states — without 30 days of log, you can't query 30-day-old snapshots even if the data files are still there.

Both properties need to be set to 30 days to fully honour the requirement. Option A (delta.timeUntilArchived) doesn't exist in Delta Lake. Option C (autoCompact) manages file sizing, not retention. Option E (enableDeletionVectors) speeds up deletes but has no bearing on how long data is kept.

The correct answer is D — a targets node in databricks.yml.

Databricks Asset Bundles use a single databricks.yml to define all resources (jobs, apps, pipelines) once, and a targets node to define per-environment overrides. Within the development target, you can use the include/exclude mechanism or resource-level overrides to deploy only one of the two jobs. The app and the second job are deployed to both environments through the shared resource definition.

Option B (separate databricks.yml files per environment) works technically but means duplicating the shared resource definitions across files — any change to a shared resource requires edits in multiple places, which is exactly the administrative overhead the question wants to avoid.

Option A (resources node) defines resources globally across all targets — it doesn't provide environment-specific filtering. Option C (variables node) parameterises values like cluster sizes or paths but doesn't control which resources are deployed to which environment.

The correct answer is C — the Databricks CLI.

Databricks Asset Bundles are deployed using the Databricks CLI (v0.205+) with the commands databricks bundle validate, databricks bundle deploy, and databricks bundle run. The CLI reads the databricks.yml file, resolves the target environment settings, and creates or updates all declared resources (jobs, pipelines, apps) in the workspace. This is the documented, supported deployment mechanism for DABs and integrates naturally into CI/CD pipelines.

Option A (Azure Developer CLI / azd) is a general Azure IaC tool with no native understanding of Databricks bundles. Option B (Git folders) syncs notebook and file content from a Git repository into a workspace — useful for code, but it doesn't deploy Lakeflow Jobs, SDP pipelines, or bundle configurations. Option D (Azure CLI) manages Azure infrastructure (resource groups, storage accounts, etc.) and has no native DAB deployment support.

The correct answer is B. The %pip install command (or pip3 in a terminal context) creates an isolated, per-session library environment in notebooks, which is the Unity Catalog-compatible approach. Unity Catalog workspaces require cluster access mode set to 'Shared' or 'Single User,' and %pip installs work seamlessly within those modes without requiring cluster restarts.

Option A (custom dependency script) introduces extra maintenance work for every environment change — exactly what the question says to avoid. Option C installs libraries at the cluster level and requires a manual restart, which disrupts other users sharing the cluster and bypasses the per-notebook isolation model that Unity Catalog recommends. Option D uploads libraries to the Workspace file system (legacy DBFS approach), which is being deprecated in favour of Unity Catalog Volumes for library storage.

The solution requires spark.readStream with format('cloudFiles') for Auto Loader, paired with .writeStream using mergeSchema=true and a checkpointLocation.

Auto Loader's cloudFiles source incrementally processes new JSON files without rescanning the entire directory. The mergeSchema option handles schema drift — when sensors add new fields, the target Delta table schema expands automatically instead of throwing a parse error. This directly addresses Contoso's requirement to 'support schema drift.'

The checkpointLocation is what gives the pipeline its resilience. Databricks writes the stream's committed offset and schema state to that path. If the cluster restarts, the engine reads the checkpoint and picks up exactly where it left off — no events are reprocessed, satisfying 'exactly-once semantics' and 'resume processing after failures without reprocessing the data.'

Without a checkpoint, the stream would restart from the beginning on every cluster bounce, which is precisely the problem Contoso is trying to eliminate.

The right ingestion tool depends on the source characteristics:

File-based telemetry and maintenance data → Auto Loader (cloudFiles). It monitors ADLS Gen2 for new arrivals, handles schema inference and evolution for the frequent schema drift, and requires minimal operational effort.

Real-time telemetry from Event Hubs → Spark Structured Streaming with the azure-eventhubs-spark connector. This provides exactly-once semantics and checkpoint-based recovery, satisfying 'resume processing after failures without reprocessing.'

Structured maintenance data from PostgreSQL → JDBC connector. Databricks supports direct JDBC reads from relational databases with pushdown predicates.

Daily CSV ERP extracts (50–100 GB) → COPY INTO or Auto Loader. Both support idempotent incremental batch loading into Delta tables with minimal code.

The correct answer is D. Breaking the pipeline into separate tasks for ingestion, cleansing, and curation is the foundation of well-designed Lakeflow Jobs pipelines. Each task should own one responsibility — when a task does too much, debugging a failure becomes a hunt through unrelated code, and retry logic becomes expensive because you re-execute work that already succeeded.

Contoso's planned changes explicitly call for 'a clear execution order and dependencies' and 'orchestrate multi-step ingestion and transformation workflows.' Separate tasks map directly to those goals: Lakeflow Jobs tracks each task's status independently, so if cleansing fails, ingestion doesn't re-run.

Option A bundles everything into one notebook, which means a curation bug forces a full re-ingestion. Option B copies logic three times — any future change must be applied in triplicate, which is a maintenance hazard. Option C forces everything through SQL MERGE, which is the wrong tool for raw-event ingestion and doesn't address cleansing or schema drift.

The correct mapping is SCD Type 1 for equipment metadata and SCD Type 2 for IoT sensor ownership history.

SCD Type 1 overwrites the existing record whenever an attribute changes — no history is kept. Contoso's requirement for equipment metadata (name, manufacturer, model, commissioning date) states 'historical values are NOT required,' which is the textbook definition of Type 1. A MERGE INTO with WHEN MATCHED THEN UPDATE handles this cleanly in Delta Lake.

SCD Type 2 creates a new row for each change, preserving the full history through effective-date or version columns. Contoso requires that 'analysts must track the full history of ownership' as sensors change hands over time — that full audit trail is only possible with Type 2. Type 3 (keeping just the previous value in an extra column) would lose earlier ownership records, so it doesn't satisfy the 'full history' requirement.

The correct answer is A. Photon is Azure Databricks' native vectorized query engine, written in C++, designed to accelerate data ingestion and SQL-heavy workloads significantly over the standard Spark JVM path. Enabling it on a job compute cluster directly addresses Contoso's requirement for 'fast and consistent performance for BI workloads' and 'production ingestion workloads that can scale automatically during telemetry spikes.'

Photon integrates transparently — no code changes are needed — and pairs well with autoscaling job clusters to handle the bursty 40,000-sensor telemetry load.

Option B contradicts the isolation requirement: Contoso explicitly needs production and development separated, not merged onto shared compute. Option C with a fixed large node gives peak capacity at all times, driving up costs even during quiet periods. Option D disabling autoscaling is the opposite of what's needed — telemetry spikes require elastic scaling, not a locked node count.