Microsoft DP-900 Practice Test 42
Question 410
A query assumes every device telemetry document contains temperature and humidity. Which principle BEST explains the correct Sparse document attributes design decision?
- Analysts translate curated data into interpretable insights.
- Flexible records may omit fields while preserving other consistent identifiers.
- JSON arrays hold ordered elements whereas objects group named properties.
- Cosmos DB supports distributed data models but partition and consistency choices matter.
Explanation
Correct Answer
B:Flexible records may omit fields while preserving other consistent identifiers. In this case the applicable decision is to support optional document fields with suitable defaults or explicit missing-value checks.
Incorrect Answers
A:Analysts translate curated data into interpretable insights. That concept explains Data analyst report design; the situation instead concerns Sparse document attributes. Assuming missing values equal zero can distort domain analysis.
C:JSON arrays hold ordered elements whereas objects group named properties. That concept explains JSON arrays and nested objects; the situation instead concerns Sparse document attributes. Assuming missing values equal zero can distort domain analysis.
D:Cosmos DB supports distributed data models but partition and consistency choices matter. That concept explains Cosmos DB for distributed JSON apps; the situation instead concerns Sparse document attributes. Assuming missing values equal zero can distort domain analysis.
Question 411
An operator must find orders with status Shipped and amount above a threshold. Select THREE statements that correctly describe the SQL SELECT filtering WHERE implementation and how it can be verified.
- Output contains only rows meeting every specified filter condition.
- Create an appropriate index on the selective lookup or join column.
- WHERE restricts rows before grouping in a SQL query.
- Separate provider engine/host operations from customer schema data and application responsibilities.
- Apply explicit SELECT projection and WHERE predicates.
- Sort by year and claim sorting is equivalent to a WHERE filter.
Explanation
Correct Answers
A:Output contains only rows meeting every specified filter condition. This is directly observable success evidence for SQL SELECT filtering WHERE.
C:WHERE restricts rows before grouping in a SQL query. This supports why the action and evidence together address SQL SELECT filtering WHERE.
E:Apply explicit SELECT projection and WHERE predicates. This is an appropriate action for the SQL SELECT filtering WHERE case. WHERE restricts rows before grouping in a SQL query.
Incorrect Answers
B:Create an appropriate index on the selective lookup or join column. This implements B tree index for lookups instead of the required SQL SELECT filtering WHERE function. WHERE restricts rows before grouping in a SQL query.
D:Separate provider engine/host operations from customer schema data and application responsibilities. This implements Azure SQL managed maintenance responsibility instead of the required SQL SELECT filtering WHERE function. WHERE restricts rows before grouping in a SQL query.
F:Sort by year and claim sorting is equivalent to a WHERE filter. This is not a safe or appropriate SQL SELECT filtering WHERE implementation. Missing a predicate may expose unrelated rows or inflate results.
Question 412
A warehouse deliberately duplicates department labels for read performance. Which principle BEST explains the correct Denormalization for analytics tradeoff design decision?
- PostgreSQL services preserve engine-specific language and compatibility semantics.
- Elastic pools support shared resource budgeting for multiple databases.
- Third normal form removes nonkey attributes dependent on other nonkey attributes.
- Denormalization trades redundancy and maintenance cost for read convenience.
Explanation
Correct Answer
D:Denormalization trades redundancy and maintenance cost for read convenience. In this case the applicable decision is to denormalize only selected analytical attributes with a refresh consistency plan.
Incorrect Answers
A:PostgreSQL services preserve engine-specific language and compatibility semantics. That concept explains Azure Database for PostgreSQL Flexible Server; the situation instead concerns Denormalization for analytics tradeoff. Casual duplication without refresh governance makes reports disagree.
B:Elastic pools support shared resource budgeting for multiple databases. That concept explains Azure SQL elastic pool sharing; the situation instead concerns Denormalization for analytics tradeoff. Casual duplication without refresh governance makes reports disagree.
C:Third normal form removes nonkey attributes dependent on other nonkey attributes. That concept explains Third normal form transitive dependency; the situation instead concerns Denormalization for analytics tradeoff. Casual duplication without refresh governance makes reports disagree.
Question 413
A business needs database continuity during a datacenter fault. After selecting the proper Azure SQL high availability and zone resiliency approach, which observation gives the clearest evidence of success?
- A supported failover maintains service within documented expectations.
- Missing values are included or excluded as business rules specify.
- Authorized app connections succeed while blocked source networks cannot connect.
- Each value can be queried and validated without splitting a cell.
Explanation
Correct Answer
A:A supported failover maintains service within documented expectations. This is the directly observable result for Azure SQL high availability and zone resiliency; managed availability still has chosen tiers and failover behavior.
Incorrect Answers
B:Missing values are included or excluded as business rules specify. This supports NULL and three-valued logic, not confirmation of Azure SQL high availability and zone resiliency. The relevant evidence is that a supported failover maintains service within documented expectations.
C:Authorized app connections succeed while blocked source networks cannot connect. This supports Azure SQL firewall and private endpoint, not confirmation of Azure SQL high availability and zone resiliency. The relevant evidence is that a supported failover maintains service within documented expectations.
D:Each value can be queried and validated without splitting a cell. This supports First normal form atomic attributes, not confirmation of Azure SQL high availability and zone resiliency. The relevant evidence is that a supported failover maintains service within documented expectations.
Question 414
An import sends null mandatory customer IDs and out-of-range tax rates. Which principle BEST explains the correct Relational constraint CHECK and NOT NULL design decision?
- Deployment models trade managed convenience for operating-system and instance control.
- At-rest encryption and TLS-in-transit protect different surfaces.
- Column and row constraints enforce business validity beyond application forms.
- A primary key enforces row identity while nonkey fields may repeat.
Explanation
Correct Answer
C:Column and row constraints enforce business validity beyond application forms. In this case the applicable decision is to define NOT NULL and appropriate CHECK constraints on columns.
Incorrect Answers
A:Deployment models trade managed convenience for operating-system and instance control. That concept explains SQL deployment choice by control plane; the situation instead concerns Relational constraint CHECK and NOT NULL. UI-only validation can be bypassed by other write clients.
B:At-rest encryption and TLS-in-transit protect different surfaces. That concept explains Transparent data encryption versus query TLS; the situation instead concerns Relational constraint CHECK and NOT NULL. UI-only validation can be bypassed by other write clients.
D:A primary key enforces row identity while nonkey fields may repeat. That concept explains Primary key row uniqueness; the situation instead concerns Relational constraint CHECK and NOT NULL. UI-only validation can be bypassed by other write clients.
Question 415
A project team should view reports without editing shared pipelines. After selecting the proper Fabric workspace permissions and capacity approach, which observation gives the clearest evidence of success?
- Trend changes are visible in chronological order.
- Product filters affect intended fact rows without unpredictable double counting.
- Scheduled runs repeat the transformation outside an author's interactive session.
- Authors and viewers have correct permissions and workloads meet expected limits.
Explanation
Correct Answer
D:Authors and viewers have correct permissions and workloads meet expected limits. This is the directly observable result for Fabric workspace permissions and capacity; fabric workloads share governance and capacity concepts across experiences.
Incorrect Answers
A:Trend changes are visible in chronological order. This supports Line chart time-series selection, not confirmation of Fabric workspace permissions and capacity. The relevant evidence is that authors and viewers have correct permissions and workloads meet expected limits.
B:Product filters affect intended fact rows without unpredictable double counting. This supports One-to-many semantic relationships, not confirmation of Fabric workspace permissions and capacity. The relevant evidence is that authors and viewers have correct permissions and workloads meet expected limits.
C:Scheduled runs repeat the transformation outside an author's interactive session. This supports Databricks collaborative notebooks, not confirmation of Fabric workspace permissions and capacity. The relevant evidence is that authors and viewers have correct permissions and workloads meet expected limits.
Question 416
A team wants the number of failures per service for each hour. Which choice BEST meets this requirement?
- Use KQL summarize with time bins and appropriate grouping.
- Use an appropriate map visual with geographic fields and data category metadata.
- Assume changing the color of a dashboard chart performs KQL aggregation.
- Use Fabric Real-Time hub to find and manage accessible streams.
Explanation
Correct Answer
A:Use KQL summarize with time bins and appropriate grouping. KQL enables time-oriented event aggregation for operational analytics. In the stated case, verification should show that counts match known events and time buckets.
Incorrect Answers
B:Use an appropriate map visual with geographic fields and data category metadata. That action primarily handles Map visual geographic measures; the given requirement is KQL summarize time-series events. KQL enables time-oriented event aggregation for operational analytics.
C:Assume changing the color of a dashboard chart performs KQL aggregation. It does not implement KQL summarize time-series events. Counting events without time filtering can misstate incident scope.
D:Use Fabric Real-Time hub to find and manage accessible streams. That action primarily handles Fabric Real-Time hub stream discovery; the given requirement is KQL summarize time-series events. KQL enables time-oriented event aggregation for operational analytics.
Question 417
Analysts must compare product categories quarter over quarter. Select TWO statements that correctly describe the OLAP aggregation over history implementation and how it can be verified.
- Give data engineers responsibility for ingestion orchestration and transformation pipelines.
- Define quality checks for missing invalid and duplicate business records.
- Reports calculate consistent totals without updating individual orders.
- Use analytical queries with grouping and historical dimensions.
- Insert a new checkout order for every report filter selection.
Explanation
Correct Answers
C:Reports calculate consistent totals without updating individual orders. This is directly observable success evidence for OLAP aggregation over history.
D:Use analytical queries with grouping and historical dimensions. This is an appropriate action for the OLAP aggregation over history case. Analytical workloads scan and aggregate many records to support decisions.
Incorrect Answers
A:Give data engineers responsibility for ingestion orchestration and transformation pipelines. This implements Data engineer ingestion pipeline instead of the required OLAP aggregation over history function. Analytical workloads scan and aggregate many records to support decisions.
B:Define quality checks for missing invalid and duplicate business records. This implements Data quality completeness and accuracy instead of the required OLAP aggregation over history function. Analytical workloads scan and aggregate many records to support decisions.
E:Insert a new checkout order for every report filter selection. This is not a safe or appropriate OLAP aggregation over history implementation. Reusing the OLTP table as an uncontrolled reporting dump can affect operations.
Question 418
A catalog tracks products that belong to multiple promotions. What is the MOST appropriate next validation or correction?
- Test duplicate enrollment prevention and correct cardinality.
- Test allowed reads denied writes and resulting audit records.
- Add one foreign key to Students and assume it represents all student-course pairs.
- Test a known customer with zero orders in output.
Explanation
Correct Answer
A:Test duplicate enrollment prevention and correct cardinality. This tests the intended result: each permitted pair is represented once and joins list associations.
Incorrect Answers
B:Test allowed reads denied writes and resulting audit records. It tests Azure SQL auditing and least privilege rather than the critical Many to many bridge table behavior. Many-to-many relationships are often resolved with a junction table.
C:Add one foreign key to Students and assume it represents all student-course pairs. This unsafe shortcut leaves the Many to many bridge table problem unresolved. Embedding lists of related IDs in one column makes constraints and joins harder.
D:Test a known customer with zero orders in output. It tests Left outer join preserving parents rather than the critical Many to many bridge table behavior. Many-to-many relationships are often resolved with a junction table.
Question 419
Changing the order date requires editing every line item. Select TWO statements that correctly describe the Second normal form partial dependency implementation and how it can be verified.
- Move attributes dependent only on OrderID into the order header table.
- Keep duplicated order header fields because a composite key always requires duplicates.
- Choose supported Azure SQL geo-replication or failover groups with realistic RPO/RTO.
- Updating an order date requires one logical header change.
- Use CREATE or ALTER as appropriate for relational schema changes.
Explanation
Correct Answers
A:Move attributes dependent only on OrderID into the order header table. This is an appropriate action for the Second normal form partial dependency case. Second normal form removes partial dependencies on a composite key.
D:Updating an order date requires one logical header change. This is directly observable success evidence for Second normal form partial dependency.
Incorrect Answers
B:Keep duplicated order header fields because a composite key always requires duplicates. This is not a safe or appropriate Second normal form partial dependency implementation. Repeated header attributes create inconsistent multirow updates.
C:Choose supported Azure SQL geo-replication or failover groups with realistic RPO/RTO. This implements Azure SQL active geo-replication tradeoff instead of the required Second normal form partial dependency function. Second normal form removes partial dependencies on a composite key.
E:Use CREATE or ALTER as appropriate for relational schema changes. This implements CREATE ALTER DROP DDL instead of the required Second normal form partial dependency function. Second normal form removes partial dependencies on a composite key.
Question 420
An enterprise plans read-only query routing to eligible replicas. Which principle BEST explains the correct Azure SQL read scale and reporting replicas design decision?
- Read scale can separate query consumption from primary writes but may have replication lag.
- Second normal form removes partial dependencies on a composite key.
- Azure SQL Database abstracts most server and engine patch operations.
- A table can enforce uniqueness on nonprimary attributes.
Explanation
Correct Answer
A:Read scale can separate query consumption from primary writes but may have replication lag. In this case the applicable decision is to evaluate supported read scale-out options under the chosen service tier.
Incorrect Answers
B:Second normal form removes partial dependencies on a composite key. That concept explains Second normal form partial dependency; the situation instead concerns Azure SQL read scale and reporting replicas. Assuming immediate consistency on all asynchronous replicas can show stale reports.
C:Azure SQL Database abstracts most server and engine patch operations. That concept explains Azure SQL Database single database PaaS; the situation instead concerns Azure SQL read scale and reporting replicas. Assuming immediate consistency on all asynchronous replicas can show stale reports.
D:A table can enforce uniqueness on nonprimary attributes. That concept explains Unique index versus primary key; the situation instead concerns Azure SQL read scale and reporting replicas. Assuming immediate consistency on all asynchronous replicas can show stale reports.