MB-820 Microsoft Dynamics 365 Business Central Developer Free Practice Exam Questions (2025 Updated)

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.

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.

Code Segment Analysis:

The AL code is trying to read JSON data from a response and process it to extract subcontracting order numbers. It uses JsonToken, JsonObject, and JsonArray to work with the JSON data.

JToken.ReadFrom(Data): This line reads the incoming JSON data and converts it into a token. It processes the full JSON body so you can start working with it.

JToken.SelectToken("results"): This line selects the part of the JSON containing the results array. The key "results" is where the JSON response data is expected to be found.

JsonArray: Once the results are extracted, they are stored as an array, and each element in the array (which is expected to contain subcontracting order numbers) is processed.

SubcontractingOrderNo: The extracted order_no from the JSON is stored in this variable.

Breakdown of Steps:

JToken.ReadFrom(Data): This step reads the entire JSON response.

JToken.SelectToken("results"): This step selects the results array from the JSON response.

JArray.AsArray(): This step converts the selected results token into a JSON array that can be iterated over.

GetValueAsText(JToken, 'order_no'): This step retrieves the order_no from each element in the array.

Correct Code Completion:

JToken.ReadFrom(Data): This is the correct method to read the incoming JSON response, as it will convert the string into a JsonToken that can be further processed.

JToken.SelectToken("results"): This is the correct method to extract the results array from the token. This method looks for the key "results" in the JSON and retrieves the relevant array.

Final Code Segment:

al

Copy code

procedure ReadJsonData(Data: text)

var

JToken: JsonToken;

JObject: JsonObject;

JArray: JsonArray;

SubcontractingOrderNo: Code[20];

begin

if Data = '' then

exit;

JToken := JToken.ReadFrom(Data); // Step 1: Read the JSON response data.

JToken := JToken.SelectToken('results'); // Step 2: Select the "results" array.

JArray := JToken.AsArray(); // Convert the token into a JSON array.

foreach JToken in JArray do begin

SubcontractingOrderNo := GetValueAsText(JToken, 'order_no'); // Retrieve the order number.

end;

end;

JToken.ReadFrom(Data): This reads the raw JSON data string and converts it into a JSON token that can be processed.

JToken.SelectToken("results"): This extracts the results array from the JSON data.

JArray.AsArray(): Converts the token into an array so we can iterate over it.

GetValueAsText(JToken, 'order_no'): Extracts the order_no value from each item in the array.

The task is to identify unwanted incoming web service calls during the last seven days. To do this, we need to look at KQL (Kusto Query Language) queries that would filter out web service calls based on the timestamp (to ensure the calls are within the last seven days) and by certain characteristics that would indicate they are unwanted, such as the wrong type of protocol (SOAP in this case, as Contoso Ltd. plans to dismiss using it).

Looking at the options:

Option A: This query selects all traces where the timestamp is within the last 7 days and where the custom dimension has a value of 'RT0008', and where the category is either 'ODataV4', 'ODataV3', or 'Api'. This query would show all API calls except SOAP, so it does not directly answer the question about unwanted calls.

Option B: This query filters for traces with a timestamp within the last 7 days, where 'RT0008' is present, and specifically looks for the category 'SOAP'. This query is correct because it directly targets SOAP calls, which are the unwanted calls according to Contoso Ltd.'s plans.

Option C: Similar to option B, this query filters for traces within the last 7 days and looks for 'RT0008' but uses the equality operator for the category 'SOAP'. This would also correctly return the unwanted SOAP calls.

Option D: This query also filters for traces within the last 7 days, but it excludes the 'ODataV4' category, which doesn't necessarily target the unwanted SOAP calls.

Option E: This query selects traces where the timestamp is within the last 7 days and the custom dimension has 'RT0008'. However, it filters out categories 'ODataV4' and 'Api', which does not directly help in identifying the unwanted SOAP calls.

Therefore, the queries that should be used to determine if there are unwanted incoming web service calls (SOAP calls) in the tenant during the last seven days are Options B and C. These queries are specific to identifying SOAP protocol usage, which is what Contoso Ltd. considers unwanted.

Here is the most logical sequence of actions for implementing the Issue Management module in Business Central and exposing the PostIssue method:

Correct Order:

Create a codeunit named "Issue Management Impl." and set the value of Access property to Internal.

This is the first step because Issue Management Impl. is the implementation layer where the actual business logic resides, and setting it to Internal ensures that it is only accessible from within the module, following best practices in encapsulation.

Create a local procedure named PostIssueImpl in the "Issue Management Impl." codeunit.

This step adds the actual PostIssueImpl method, which contains the core logic of posting an issue.

Create a codeunit named "Issue Management" and set the value of Access property to Public.

After defining the implementation logic, you need to create a public-facing Issue Management codeunit to expose the service externally.

Create a PostIssue procedure in the "Issue Management" codeunit, and in it call the PostIssueImpl method.

Lastly, expose the PostIssue method in the Issue Management codeunit, which will internally call the PostIssueImpl method, completing the chain.

In Business Central development using AL (the language for Business Central extensions), the use of access modifiers defines how variables and procedures are accessed within and outside of an object or codeunit.

Access Modifiers in AL:

Public: A public variable can be accessed from any object or codeunit within the same module or extension.

Protected: This restricts access to the current object and objects that inherit from the current object. However, in AL (at least in versions used for Business Central), the Protected access modifier is used with methods but not variables.

Internal: This modifier restricts the visibility to the current extension. This means that variables or methods declared as internal can only be accessed from within the same extension. This is appropriate when you want to provide functionality that is shared within the extension but not exposed externally.

Local: This restricts the variable or method to the current object or method where it is declared. It cannot be accessed from anywhere else, even within the same extension.

Scenario Justification:

In the scenario for Contoso, Ltd., IssueTotal is a global variable in the ISSUE BASE extension, and the ISSUE EXT extension needs to access it. Therefore, the variable cannot be declared as Local, because this would restrict access to just the current object (or method).

Using Public would expose the variable outside of the extension, which is unnecessary because you only want other parts of the extension (specifically the ISSUE EXT extension) to have access.

The best choice in this case is Internal because it restricts access to the variable to within the same extension, which includes the base extension and any dependent extensions like ISSUE EXT. It strikes the right balance between visibility and encapsulation.

Microsoft Dynamics 365 Business Central Developer References:

Access Modifiers in AL: Microsoft's documentation on AL provides the details on access modifiers, where it is specified that internal variables can be accessed within the extension, and the public variable is accessible across all extensions【source: Microsoft Learn on AL Programming】.

Best Practices for AL Development: Business Central development best practices suggest keeping variables internal unless they need to be accessed outside of the current extension【source: Microsoft Learn on AL development guidelines】.

In Microsoft Dynamics 365 Business Central, when configuring snapshot debugging, it is crucial that the parameters in the configuration file are correctly set. From the options provided, the issue with the debugger not starting correctly is most likely due to an incorrect "userId" parameter.

Option A is the cause of the problem. The "userId" parameter must be the GUID of the user, not the username. The snapshot debugger needs the exact GUID to attach to the right session for debugging.

Option B is incorrect because "breakOnNext" set to "WebClient" is a valid setting. This tells the debugger to break on the next client action in the web client, which is a typical scenario.

Option C is not the cause of the problem. The "userId" parameter is meant to specify which user session to debug, and this works in conjunction with the "breakOnNext" parameter.

Option D is incorrect as the "executionContext" parameter does not need to be set to "Debug" for snapshot debugging to work. "DebugAndProfile" is a valid value for the "executionContext" parameter, as it allows for debugging and collecting performance information.

Therefore, the reason why the debugger does not start correctly is due to Option A: The "userId" parameter must have the GUID of the user specified, not the username.

 Upgrade codeunit trigger: OnValidateUpgradePerDatabase

Since the question specifies that you are handling data upgrades, and you need to use validation before upgrading at the database level, the correct choice is OnValidateUpgradePerDatabase. This method ensures that the upgrade process is validated before applying to the entire database, making it more efficient when data affects multiple companies or structures.

 DataTransfer method to use: CopyRows

CopyRows is the appropriate method when you are handling large data transfers between tables, especially in an upgrade scenario where you are migrating or transferring data from one table to another. It copies entire rows of data and is optimal for bulk data operations during upgrades.