Implement Data Access by Using Azure Cosmos DB for NoSQL SDKs DP-420 Practice Questions (Page 2)

Questions 6–10

1. 6application · medium

   A banking application processes fund transfers. Each transfer requires updating two account documents in Azure Cosmos DB for NoSQL: debiting one account and crediting another. The team must ensure that both updates succeed or neither is applied. They also need to handle the case where the source account has insufficient funds. Which SDK feature should they use?

   • AUse a bulk operation to send both updates at once.
   • BUse a stored procedure that runs on the server and updates both accounts.
   • CUse two separate point operations and rely on the application to roll back if the second fails.
   • DUse a transactional batch that includes both account updates and a condition that checks the source account balance.
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2. 7expert · hard

   An application uses Azure Cosmos DB for NoSQL and experiences intermittent HTTP 429 errors during peak hours. The team has already implemented retry logic that respects the Retry-After header. However, some operations still fail after multiple retries. The team wants to ensure that no data is lost and that the application remains responsive. What should they do?

   • AIncrease the provisioned RUs to eliminate 429 errors.
   • BQueue the failed operations and retry them later with exponential backoff, while monitoring the queue length.
   • CSwitch to a different consistency level to reduce the number of 429 errors.
   • DUse a stored procedure to perform the operations, as it will not be subject to rate limiting.
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4. 8application · medium

   A developer is optimizing a query that filters by a non-partition-key property. The query is slow and consumes many RUs. The developer wants to understand why the query is expensive and what to improve. What should the developer do first?

   • AEnable query metrics in QueryRequestOptions and review the output.
   • BChange the query to use a point read by id.
   • CIncrease the container's RU/s.
   • DAdd a composite index on the filtered property.
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5. 9foundation · easy

   Which consistency level can be overridden per request in Azure Cosmos DB?

   • AAny consistency level that is weaker than the account's default consistency level.
   • BAny consistency level, regardless of the account default.
   • COnly the Strong consistency level.
   • DOnly the Eventual consistency level.
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6. 10application · medium

   An e-commerce app uses Azure Cosmos DB for NoSQL. When a customer places an order, the app must create an order item and decrement the product inventory item in the same logical partition. If either operation fails, neither should be applied. The app must also ensure that the inventory decrement does not make the quantity negative. What should the developer use?

   • AA stored procedure that creates the order and updates inventory without a condition.
   • BA transactional batch with a create operation for the order and a patch operation with a condition on the inventory quantity.
   • CTwo separate point operations: create the order first, then update inventory.
   • DA bulk operation that includes both the create and the update.
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