DP-420 sample exam questions

The community answer lists only C, but two actions are required. A trigger must be registered as a pre-trigger, and Cosmos DB triggers never run automatically, so each create request must name the trigger in RequestOptions (PreTriggers). Function naming, access conditions and session consistency do not invoke triggers.

An item sets its own expiry with the ttl property, in seconds, so two hours is 7200. defaultTimeToLive is a container setting, and the container must have TTL enabled for an item's ttl to take effect.

Transactions in Cosmos DB, such as stored procedures and transactional batch, are scoped to a single logical partition, so items grouped in the same logical partition can be read and written in one transaction. Physical partitions are managed by the service; containers and databases span partitions.

az cosmosdb failover-priority-change sets the region order, and --failover-policies lists each region with its priority. Priority 0 is the write region, so centralus=0 moves writes from East US to Central US.

Deterministic encryption on taxId produces the same ciphertext for the same value, so equality queries work. Randomized encryption on creditCard produces different ciphertext each time. CreateAsync only creates a container and fails with a conflict if it already exists; it never updates the policy.

Azure Data Factory has a REST connector as a source and a Cosmos DB for NoSQL sink, and can run on a weekly schedule trigger. Azure Migrate and Database Migration Assistant target server or SQL database migrations, not REST-to-Cosmos DB data copies.

No. The change feed trigger with Event Hubs output creates a stream, but Event Hubs cannot be a Stream Analytics reference data input. Reference data requires Blob Storage or SQL Database, so the data would need to be written to one of those.

Embedding the up-to-ten books in each author item inside one container lets a single point read return an author with all books, which minimizes RU cost. Writes to one item are transactional. Separate containers or relationship items need cross-container reads and cannot be updated transactionally.

A query with an equality filter and several range filters is optimized by one composite index per range property, each starting with the equality property. The existing index covers firstName and age, so add firstName then _ts. Direction on the range filter property does not affect this query.

Azure Synapse Link with the analytical store gives a column store copy of the data that Spark can query without consuming RUs, so web apps are unaffected. In Spark, a table using cosmos.olap reads the analytical store. cosmos.oltp hits the transactional store and affects performance.

Disabling key-based metadata writes means control plane changes must go through Azure Resource Manager with Microsoft Entra identities, so audit logs record the security principal. Account keys carry no user identity. The setting is an account property, so it is changed with az cosmosdb update.

Account keys are strings, so they are stored in Key Vault as a secret. Keys are cryptographic keys used for wrap, unwrap and sign operations, and certificates are X.509 objects. A key vault secret can be referenced by apps without exposing the value.

A good partition key has high cardinality and spreads writes evenly while matching common queries. Device ID gives many distinct values and fits per-device telemetry queries. Timestamp creates hot partitions for current writes, and humidity or temperature are measurements with few repeated values.

Gateway mode over HTTPS works through a single endpoint on port 443, so it suits apps behind restrictive firewalls or limited ports. Direct mode uses TCP across many ports and replicas, and direct mode over HTTPS is only for legacy cases. The case study context favors gateway mode.

Multiple change feed triggers can share one lease container (same leaseCollectionName) when each function uses a different leaseCollectionPrefix, so each function gets its own independent change feed checkpoints. Different lease collections would add cost, and the same prefix would make functions split the work.