DP-420 Practice Questions

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Box 1: ORDER BY c.name DESC, c.age DESC

Queries that have an ORDER BY clause with two or more properties require a composite index.

The following considerations are used when using composite indexes for queries with an ORDER BY

clause with two or more properties:

If the composite index paths do not match the sequence of the properties in the ORDER BY clause,

then the composite index can't support the query.

The order of composite index paths (ascending or descending) should also match the order in the

ORDER BY clause.

The composite index also supports an ORDER BY clause with the opposite order on all paths.

Box 2: At the same time as the item creation

Azure Cosmos DB supports two indexing modes:

Consistent: The index is updated synchronously as you create, update or delete items. This means

that the consistency of your read queries will be the consistency configured for the account.

None: Indexing is disabled on the container.

Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/index-policy

Azure Cosmos DB supports queries with parameters expressed by the familiar @ notation.

Parameterized SQL provides robust handling and escaping of user input, and prevents accidental

exposure of data through SQL injection.

For example, you can write a query that takes lastName and address.state as parameters, and

execute it for various values of lastName and address.state based on user input.

SELECT *

FROM Families f

WHERE f.lastName = @lastName AND f.address.state = @addressState

Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/sql/sql-query-parameterized-queries

Use a partition key with a random suffix. Distribute the workload more evenly is to append a random

number at the end of the partition key value. When you distribute items in this way, you can perform

parallel write operations across partitions.

Incorrect Answers:

A: You will also not like to partition the data on “DateTime”, because this will create a hot partition.

Imagine you have partitioned the data on time, then for a given minute, all the calls will hit one

partition. If you need to retrieve the data for a customer, then it will be a fan-out query because data

may be distributed on all the partitions.

B: Senser1Value has only two values.

C: All the devices could have the same manufacturer.

Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/sql/synthetic-partition-keys

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Box 1: Yes

VM1 is on vnet1.subnet1 which has the Endpoint Status enabled.

Box 2: No

Only virtual network and their subnets added to Azure Cosmos account have access. Their peered

VNets cannot access the account until the subnets within peered virtual networks are added to the

account.

Box 3: No

Only virtual network and their subnets added to Azure Cosmos account have access.

Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/how-to-configure-vnet-serviceendpoint

Bounded staleness is frequently chosen by globally distributed applications that expect low write

latencies but require total global order guarantee. Bounded staleness is great for applications

featuring group collaboration and sharing, stock ticker, publish-subscribe/queueing etc.

Scenario: Application updates in con-product frequently cause HTTP status code 429 "Too many

requests". You discover that the 429 status code relates to excessive request unit (RU) consumption

during the updates.

Reference:

https://docs.microsoft.com/en-us/azure/cosmos-db/consistency-levels

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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

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Box 1: Yes

"path": "/*" is in includePaths.

Include the root path to selectively exclude paths that don't need to be indexed. This is the

recommended approach as it lets Azure Cosmos DB proactively index any new property that may be

added to your model.

Box 2: No

"path": "/firstName/?" is in excludePaths.

Box 3: Yes

"path": "/address/city/?" is in includePaths

Reference: https://docs.microsoft.com/en-us/azure/cosmos-db/index-policy

Reference:

https://github.com/microsoft/MCW-Cosmos-DB-Real-Time-Advanced-Analytics/blob/main/Handson%20lab/HOL%20step-by%20step%20-%20Cosmos%20DB%20real-

time%20advanced%20analytics.md

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