Microsoft Microsoft Certified: Azure Cosmos DB Developer Specialty DP-420 Questions & Answers

• Question 61:

  You have a database in an Azure Cosmos DB for NoSQL account that is configured for multi-region writes.

  You need to use the Azure Cosmos DB SDK to implement the conflict resolution policy for a container. The solution must ensure that any conflict sent to the conflict feed.

  Solution:

  1.

  You set ConfilictResolutionMode to Custom.

  2.

  You Set ResolutionProcedures to a custom stored procedure.

  3.

  You configure the custom stored procedure to use the conflictingItems parameter to resolve conflict.

  Does this meet the goal?

  A. Yes

  B. No

  Correct Answer: A

  Setting ConflictResolutionMode to Custom and configuring a custom stored procedure with the "conflictingItems" parameter will allow you to implement a custom conflict resolution policy. This will ensure that any conflicts are sent to the conflict feed for resolution.

• Question 62:

  You have a database in an Azure Cosmos DB for NoSQL account that is configured for multi-region writes.

  You need to use the Azure Cosmos DB SDK to implement the conflict resolution policy for a container. The solution must ensure that any conflict sent to the conflict feed.

  Solution: You set ConfilictResolutionMode to Custom and you use the default settings for the policy.

  Does this meet the goal?

  A. Yes

  B. No

  Correct Answer: B

  Setting ConflictResolutionMode to Custom and using the default settings for the policy will not ensure that conflicts are sent to the conflict feed. You need to define a custom stored procedure using the "conflictingItems" parameter to handle conflicts properly.

• Question 63:

  You plan to store order data in Azure Cosmos DB for NoSQL account. The data contains information about orders and their associated items.

  You need to develop a model that supports order read operations. The solution must minimize the number or requests.

  A. Create a single database that contains one container. Store orders and order items in separate documents in the container.

  B. Create a single database that contains one container. Create a separate document for each order and embed the order items into the order documents.

  C. Create a database for orders and a database for order items.

  D. Create a single database that contains a container for order and a container for order items.

  Correct Answer: B

  Azure Cosmos DB is a multi-model database that supports various data models, such as documents, key-value, graph, and column-family3. The core content- model of Cosmos DB's database engine is based on atom-record-sequence (ARS), which allows it to store and query different types of data in a flexible and efficient way3. To develop a model that supports order read operations and minimizes the number of requests, you should consider the following factors:

  1.

  The size and shape of your data

  2.

  The frequency and complexity of your queries

  3.

  The latency and throughput requirements of your application

  4.

  The trade-offs between storage efficiency and query performance

  Based on these factors, one possible model that you could implement is B. Create a single database that contains one container. Create a separate document for each order and embed the order items into the order documents.

  This model has the following advantages:

  1.

  It stores orders and order items as self-contained documents that can be easily retrieved by order ID1.

  2.

  It avoids storing redundant data or creating additional containers for order items1.

  3.

  It allows you to view the order history of a customer with simple queries1.

  4.

  It leverages the benefits of embedding data, such as reducing the number of requests, improving query performance, and simplifying data consistency2.

  This model also has some limitations, such as: It may not be suitable for some order items that have data that is greater than 2 KB, as it could exceed the maximum document size limit of 2 MB2. It may not be optimal for scenarios where order items need to be queried independently from orders or aggregated by other criteria2. It may not support transactions across multiple orders or customers, as transactions are scoped to a single logical partition2. Depending on your specific use case and requirements, you may need to adjust this model or choose a different one. For example, you could use a hybrid data model that combines embedding and referencing data2, or you could use a graph data model that expresses entities and relationships as vertices and edges.

• Question 64:

  You have a container named container1 in an Azure Cosmos DB for NoSQL account named account1 that is set to the session default consistency level. The average size of an item in container1 is 20 KB.

  You have an application named App1 that uses the Azure Cosmos DB SDK and performs a point read on the same set of items in container1 every minute.

  You need to minimize the consumption of the request units (RUs) associated to the reads by App1.

  What should you do?

  A. In account1, change the default consistency level to bounded staleness.

  B. In App1, change the consistency level of read requests to consistent prefix.

  C. In account1, provision a dedicated gateway and integrated cache

  D. In App1, modify the connection policy settings.

  Correct Answer: B

  The cost of a point read for a 1 KB item is 1 RU. The cost of other operations depends on factors such as item size, indexing policy, consistency level, and query complexity1. To minimize the consumption of RUs, you can optimize these

  factors according to your application needs.

  For your scenario, one possible way to minimize the consumption of RUs associated to the reads by App1 is to change the consistency level of read requests to consistent prefix. Consistent prefix is a lower consistency level than session,

  which is the default consistency level for Azure Cosmos DB. Lower consistency levels consume fewer RUs than higher consistency levels2. Consistent prefix guarantees that reads never see out-of-order writes and that monotonic reads are

  preserved1. This may be suitable for your application if you can tolerate some eventual consistency.

• Question 65:

  DRAG DROP

  You have an app that stores data in an Azure Cosmos DB Core (SQL) API account The app performs queries that return large result sets.

  You need to return a complete result set to the app by using pagination. Each page of results must return 80 items.

  Which three actions should you perform in sequence? To answer, move the appropriate actions from the list of actions to the answer area and arrange them in the correct order.

  Select and Place:

  

  Correct Answer:

  

  When DefaultTimeToLive is -1 then your Time to Live setting is On (No default)

  Time to Live on a container, if present and the value is set to "-1", it is equal to infinity, and items don't expire by default.

  Time to Live on an item:

  This Property is applicable only if DefaultTimeToLive is present and it is not set to null for the parent container.

  If present, it overrides the DefaultTimeToLive value of the parent container.

  Reference:

  https://docs.microsoft.com/en-us/azure/cosmos-db/sql/time-to-liveExplanation:

  Step 1: Configure the MaxItemCount in QueryRequestOptions

  You can specify the maximum number of items returned by a query by setting the MaxItemCount. The MaxItemCount is specified per request and tells the query engine to return that number of items or fewer.

  Box 2: Run the query and provide a continuation token

  In the .NET SDK and Java SDK you can optionally use continuation tokens as a bookmark for your query's progress. Azure Cosmos DB query executions are stateless at the server side and can be resumed at any time using the continuation

  token.

  If the query returns a continuation token, then there are additional query results.

  Step 3: Append the results to a variable

  Reference:

  https://docs.microsoft.com/en-us/azure/cosmos-db/sql/sql-query-pagination

• Question 66:

  DRAG DROP

  You have an Azure Cosmos DB Core (SQL) API account that is configured for multi-region writes. The account contains a database that has two containers named container1 and container2.

  The following is a sample of a document in container1:

  {

  "customerId": 1234,

  "firstName": "John",

  "lastName": "Smith",

  "policyYear": 2021

  }

  The following is a sample of a document in container2:

  {

  "gpsId": 1234,

  "latitude": 38.8951,

  "longitude": -77.0364

  }

  You need to configure conflict resolution to meet the following requirements:

  1.

  For container1 you must resolve conflicts by using the highest value for policyYear.

  2.

  For container2 you must resolve conflicts by accepting the distance closest to latitude: 40.730610and longitude: -73.935242.

  3.

  Administrative effort must be minimized to implement the solution.

  What should you configure for each container? To answer, drag the appropriate configurations to the correct containers. Each configuration may be used once, more than once, or not at all. You may need to drag the split bar between panes

  or scroll to view content.

  NOTE: Each correct selection is worth one point.

  Select and Place:

  

  Correct Answer:

  

  Box 1: Last Write Wins (LWW) (default) mode

  Last Write Wins (LWW): This resolution policy, by default, uses a system-defined timestamp property. It's based on the time-synchronization clock protocol.

  Box 2: Merge Procedures (custom) mode

  Custom: This resolution policy is designed for application-defined semantics for reconciliation of conflicts. When you set this policy on your Azure Cosmos container, you also need to register a merge stored procedure. This procedure is

  automatically invoked when conflicts are detected under a database transaction on the server. The system provides exactly once guarantee for the execution of a merge procedure as part of the commitment protocol.

  Reference:

  https://docs.microsoft.com/en-us/azure/cosmos-db/conflict-resolution-policies

  https://docs.microsoft.com/en-us/azure/cosmos-db/sql/how-to-manage-conflicts

• Question 67:

  HOTSPOT

  You provision Azure resources by using the following Azure Resource Manager (ARM) template.

  

  For each of the following statements, select Yes if the statement is true. Otherwise, select No.

  NOTE: Each correct selection is worth one point.

  Hot Area:

  

  Correct Answer:

  

  Box 1: No

  An alert is triggered when the DB key is regenerated, not when it is used.

  Note: The az cosmosdb keys regenerate command regenerates an access key for a Azure Cosmos DB database account.

  Box 2: No

  Only an SMS action will be taken.

  Emailreceivers is empty so no email action is taken.

  Box 3: Yes

  Yes, an alert is triggered when the DB key is regenerated.

  Reference:

  https://docs.microsoft.com/en-us/cli/azure/cosmosdb/keys

• Question 68:

  HOTSPOT

  You have an Azure Cosmos DB Core (SQL) API account named account1 that has the disableKeyBasedMetadataWriteAccessproperty enabled.

  You are developing an app named App1 that will be used by a user named DevUser1 to create containers in account1. DevUser1 has a non-privileged user account in the Azure Active Directory (Azure AD) tenant.

  You need to ensure that DevUser1 can use App1 to create containers in account1.

  What should you do? To answer, select the appropriate options in the answer area.

  NOTE: Each correct selection is worth one point.

  Hot Area:

  

  Correct Answer:

  

  Box 1: Resource tokens

  Resource tokens provide access to the application resources within a database. Resource tokens:

  Provide access to specific containers, partition keys, documents, attachments, stored procedures, triggers, and UDFs.

  Box 2: Azure Resource Manager API

  You can use Azure Resource Manager to help deploy and manage your Azure Cosmos DB accounts, databases, and containers.

  Incorrect Answers:

  The Microsoft Graph API is a RESTful web API that enables you to access Microsoft Cloud service resources.

  Reference:

  https://docs.microsoft.com/en-us/azure/cosmos-db/secure-access-to-data

  https://docs.microsoft.com/en-us/rest/api/resources/

• Question 69:

  HOTSPOT

  You have an Azure Cosmos DB Core (SQL) account that has a single write region in West Europe.

  You run the following Azure CLI script.

  

  For each of the following statements, select Yes if the statement is true. Otherwise, select No.

  NOTE: Each correct selection is worth one point.

  Hot Area:

  

  Correct Answer:

  

  Box 1: Yes

  The Automatic failover option allows Azure Cosmos DB to failover to the region with the highest failover priority with no user action should a region become unavailable.

  Box 2: No

  West Europe is used for failover. Only North Europe is writable.

  To Configure multi-region set UseMultipleWriteLocations to true.

  Box 3: Yes

  Provisioned throughput with single write region costs $0.008/hour per 100 RU/s and provisioned throughput with multiple writable regions costs $0.016/per hour per 100 RU/s.

  Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/sql/how-to-multi-master https://docs.microsoft.com/en-us/azure/cosmos-db/optimize-cost-regions

• Question 70:

  HOTSPOT

  You have a database in an Azure Cosmos DB Core (SQL) API account.

  You plan to create a container that will store employee data for 5,000 small businesses. Each business will have up to 25 employees. Each employee item will have an emailAddressvalue.

  You need to ensure that the emailAddressvalue for each employee within the same company is unique.

  To what should you set the partition key and the unique key? To answer, select the appropriate options in the answer area.

  NOTE: Each correct selection is worth one point.

  Hot Area:

  

  Correct Answer:

  

  Box 1: CompanyID After you create a container with a unique key policy, the creation of a new or an update of an existing item resulting in a duplicate within a logical partition is prevented, as specified by the unique key constraint. The partition key combined with the unique key guarantees the uniqueness of an item within the scope of the container.

  For example, consider an Azure Cosmos container with Email address as the unique key constraint and CompanyID as the partition key. When you configure the user's email address with a unique key, each item has a unique email address within a given CompanyID. Two items can't be created with duplicate email addresses and with the same partition key value.

  Box 2: emailAddress

  Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/unique-keys