MB-820 Sample Questions Answers

• In line 13, replace the Add method with Insert. = NO
• In line 15, replace the WriteTo method with ReadFrom. = NO
• Change the ItemObject variable type from JsonObject to JsonToken. = NO
• Move line 08 in the beginning of REPEAT .. UNTIL. = YES

The provided code is intended to serialize a list of items from the Item table into a JSON array format. Here is a breakdown of the code and the necessary corrections:

• In line 13, "ItemsArray.Add(ItemObject)": This line is correctly using the Add method to add the ItemObject to the ItemsArray. The Add method is the correct method to use for adding items to a JsonArray. Therefore, there is no need to replace Add with Insert.
• In line 15, "ItemsArray.WriteTo(RequestText)": The WriteTo method is used correctly to serialize the ItemsArray into a JSON formatted string and store it in the RequestText variable. The ReadFrom method is used for the opposite operation, i.e., to deserialize a JSON formatted string into a JsonArray, which is not the goal in this context. Hence, no change is needed here.
• Change the ItemObject variable type from JsonObject to JsonToken: The ItemObject variable is intended to hold JSON objects representing individual items, making JsonObject the appropriate type. JsonToken is not a type used in this context within AL for Business Central, and thus the variable type should remain as JsonObject.
• Move line 08, "Clear(ItemObject)": This line should be moved inside the repeat loop to ensure that the ItemObject is cleared for each item in the loop. Placing it before the repeat would only clear it once before the loop starts, which could lead to incorrect serialization as the previous item's properties would not be cleared from the ItemObject.

The logic for serializing records into JSON is a common operation when interfacing with APIs or web services in Business Central, and the pattern shown in the code is typical for such operations.

For the Install codeunit required for the extension used for installing or updating the Housekeeping app, you should use the following data type and declaration:

• Data type for information: ModuleInfo
• Start of the declaration of the method or procedure to perform the tasks: local procedure

In AL language, which is used for developing extensions in Business Central, an Install codeunit is a special type of codeunit that is used to handle installation or upgrade logic for an extension.

• ModuleInfo is a data type that contains information about the current extension, such as its version. It is typically used within the OnInstallAppPerCompany or OnUpgradePerCompany triggers of an Install codeunit to determine if the app is being installed for the first time or upgraded.
• A local procedure within an Install codeunit is a method that is only accessible within the codeunit itself. It is not visible to other objects or extensions. This is suitable for tasks that are internal to the installation process and should not be exposed globally.

These selections align with the requirements of handling installation and update procedures in a controlled and encapsulated manner within Business Central extensions.

codeunit 52102 "POS API Management"

{

Access = Public;

Permissions = TableData "POS Information" = rwdx;

trigger OnRun()

begin

readAPI();

end;

procedure readAPI()

begin

// Your code here to read from the POS API

end;

}

var

TempBlob: Codeunit "Temp Blob";

IncidentOutStream: OutStream;

IncidentInStream: InStream;

ImageFilter, FileName: Text;

begin

// Initialize the TempBlob and streams

TempBlob.CreateOutStream(IncidentOutStream);

Rec.Image.ExportStream(IncidentOutStream); // 'Rec' refers to the current Room Incident record

TempBlob.CreateInStream(IncidentInStream);

// Set the filters and filename for the image

ImageFilter := 'Image Files (*.bmp,*.jpg,*.jpeg,*.gif)|*.bmp;*.jpg;*.jpeg;*.gif';

FileName := 'Customer Picture';

// Prompt the user to download the image

if not DownloadFromStream(IncidentInStream, '', 'Download Incident Picture', '', ImageFilter, FileName) then

Error('Unable to download the image.');

end;

For the requirements provided, the appropriate page types should be selected as follows:

• Display relevant insights in the Housekeeping Role Center: HeadlinePart
• Display the additional information for the Room table: FactBox
• Configure the first installation: StandardDialog

Comprehensive Detailed ExplanationIn the context of Microsoft Dynamics 365 Business Central, page types are crucial for determining how information is presented to the user.

• HeadlinePart: This page type is designed to display key data and insights in a concise and visually appealing manner, often used in Role Centers to highlight important information. It is suitable for the Housekeeping Role Center to display relevant insights.
• FactBox: This page type is used to display supplementary information related to a selected record in the main part of the page. It's often used to show additional details about a record in a list, card, or document page. In this scenario, it is suitable for showing additional information about a specific Room when viewing the Room table.
• StandardDialog: This is a page type that provides a modal dialog for user interaction, commonly used for setup wizards, confirmations, and input forms that require user action before proceeding. This is appropriate for configuring the first installation, where a step-by-step guided interaction is necessary.

In Business Central, fields in tables are assigned specific data types that determine the kind of data they can store. For the Non-conformity table mentioned in the case study, the following data types should be used:

• Date for the Non-Conformity Date field: This is because the Non-conformity Date field is required to store only the date when the non-conformity was recorded. The Date data type is appropriate for storing dates without times.
• Code for the Non-Conformity Number field: The Non-conformity Number field is described to use alphanumeric values with a format that includes "NC" and the year, like "NC24-001". In Business Central, the Code data type is used for fields that store alphanumeric keys. It is a text field with a limited length, which makes it suitable for number series that contain letters and numbers.

Other options are not suitable:

• A. Integer for the Non-conformity Number field: This would not be appropriate because the Non-conformity Number includes alphanumeric characters and not just integers.
• B. DateTime for the Non-Conformity Date field: This is not correct because there is no requirement to store the time alongside the date.
• C. Char for the Non-Conformity Number field: Char data type is not typically used in Business Central for number series or identifiers. The Code data type is preferred for this purpose.

In the context of Microsoft Dynamics 365 Business Central, an extension may not appear in the tenant for several reasons, particularly after an upgrade to a new major version.

• Option A suggests that the extension was published as a DEV extension, which typically would not cause it to disappear after an upgrade because DEV extensions are intended for development and testing within sandbox environments.
• Option B indicates that the extension was not compatible with the new version within 60 days of the first notification. This is a likely reason because Microsoft enforces compatibility rules, and extensions that are not made compatible within the specified timeframe might be removed or disabled.
• Option C refers to the extension being published as a PTE (Per-Tenant Extension) and mentions the Platform parameter not being updated. This could cause issues, but not specifically the disappearance of the extension after an upgrade.
• Option D expands on Option C by adding that both the Platform and Runtime parameters were not updated in the application file. This is a critical aspect because if these parameters are not correctly set to indicate compatibility with the new version of Business Central, the extension could be disabled or removed.
• Option E is similar to Option B but mentions a 90-day period. This option does not align with standard Business Central practices for version compatibility requirements.

Therefore, the two possible reasons for the disappearance of the extension in the tenant after an upgrade are that the extension was not compatible with the new version within the required timeframe (Option B) and that the extension was published as a PTE without the Platform and Runtime parameters being updated (Option D).

To correctly write the code to call the subcontractor's REST API, you would need to set the Authorization header with the base64 encoded username and password for basic authentication. The code segment indicates the use of the Base64Convert codeunit to convert the username and password to base64 format, which is then prefixed with "Basic " to form the proper Authorization header value.

The correct method to add the Authorization header to the RequestHeaders would be:

RequestHeaders.Add('Authorization', 'Basic ' + Base64Convert.ToBase64(Username + ':' + Password));

And the correct method to set the httpContent with the body of the request would be:

httpContent.WriteFrom(Body);

These are the necessary steps to form a well-structured HTTP request for basic authentication and to include the body of the request in the API call.

The correct sequence of actions to configure telemetry for the SaaS tenant and test whether the ingested signals are displayed would be:

• Create an Azure Application Insights instance by using the Azure Portal in the Customer's subscription.
• Select the environment in the Admin Center and place the connection string in the Application Insights Connection String field.
• Select the Application Insights instance, select Logs and then inspect the Traces table.

To set up telemetry for a SaaS tenant using Azure Application Insights, you need to follow these steps:

• Create an Azure Application Insights instance: This is the first step where you create an instance in Azure that will collect the telemetry data. This should be done in the customer's Azure subscription because it's their data that you're monitoring.
• Configure the SaaS tenant to use the created Application Insights instance: This involves entering the correct connection string in the Business Central Admin Center so that telemetry data from the tenant is sent to the Application Insights instance.
• Verify that telemetry is being collected: After configuring, you would check if the telemetry is arriving as expected by inspecting the Traces table in the Azure Application Insights instance. The 'Traces' table holds the telemetry data, which you can query to verify that the correct signals are being ingested.

In the context provided by the case study, when calling an API action from a mobile application, the correct format for a POST request to an action in Business Central typically involves specifying the entity (/issues), the ID of the entity (88122e0e-5796-ec11-bb87-000d3a392eb5), and the action to be called (/Copy). The action name should match the exact name as defined in the AL code, which is case-sensitive.

• Option A is incorrect because it uses a non-standard format for the action call.
• Option B uses the PATCH method, which is generally used for update operations, not for calling actions.
• Option C is correct as it uses the POST method, which is appropriate for calling actions, and correctly specifies the entity, ID, and action name.
• Option D is incorrect because the action name /copy is in lowercase, while AL is case-sensitive, and it should match the case exactly as defined in the code.
• Option E incorrectly adds 'MicrosoftNAV' before the action name, which is not standard for calling actions in Business Central APIs.

Hence, the correct action to use when calling the Issue API action from the mobile application is given in Option C.

In Business Central, when you need to handle the removal of fields and procedures to ensure that other extensions are not affected by these changes, you typically follow a two-step deprecation process. This allows other developers and users to adapt to the changes before they are fully enforced. Here are the steps to handle the removal:

• Mark as Obsolete: In the first version where the decision to remove the field or procedure is made, you set the ObsoleteState to Pending and provide an ObsoleteReason. This doesn't remove the feature but indicates to users and developers that it will be removed in the future. This step is crucial for backward compatibility.
• Removal: In a subsequent version, after users have had time to adapt to the deprecation warning, you can then remove the field or procedure or set the ObsoleteState to Removed.

Based on these guidelines, here are the three actions you should perform in sequence:

• Set the Description field as ObsoleteState = Pending and ObsoleteReason = 'Not in use' in version 2.0.0.0.
• Set the Clone procedure as ObsoleteState = Pending and ObsoleteReason = 'Not in use' in version 2.0.0.0.
• Remove the Description field from the Issue table in version 2.0.0.1.

These steps will ensure that anyone using the Description field or Clone procedure will receive a warning about the pending deprecation before it is actually removed, thereby minimizing the impact on other extensions and providing a clear path for migration.

When handling the removal of fields and procedures in Microsoft Dynamics 365 Business Central, the process should be carried out in a way that allows other extensions or dependent features to adapt to the changes without causing immediate failures.

• Set Obsolete State and Reason for Description Field (Version 2.0.0.0): The first step involves marking the Description field as obsolete by setting the ObsoleteState to 'Pending'. This is a non-breaking change, signaling to other developers and users that the field is planned for removal in a future version. An ObsoleteReason should also be provided to explain why the field is being deprecated.
• Set Obsolete State and Reason for Clone Procedure (Version 2.0.0.0): Similarly, the Clone procedure should be marked as obsolete with the ObsoleteState set to 'Pending'. This indicates that the procedure is no longer in use and will be removed in the future. Providing an ObsoleteReason is best practice as it explains the rationale behind the decision.
• Remove the Description Field (Version 2.0.0.1): In the subsequent version, after the developers and users have been given time to adapt to the deprecation notice, the Description field can be safely removed from the Issue table. This is considered a breaking change, hence it is done after the field has been marked as obsolete in a previous version.

The reason for not removing the Description field and Clone procedure immediately in version 2.0.0.0 is to avoid causing runtime errors for any extensions or integrations that may depend on these components. By following this sequence, you provide a clear deprecation path that helps maintain the stability of the overall system while evolving the schema.