MB-820 Microsoft Dynamics 365 Business Central Developer Questions and Answers

When developing an app for Microsoft AppSource, it is crucial to adhere to specific guidelines and standards to ensure compatibility and compliance. The three code analyzers you should activate are:

CodeCop (A): This is the default analyzer for AL language extensions. It enforces the AL Coding Guidelines, ensuring that the code follows best practices for readability, maintainability, and performance. It checks for a wide range of issues, from syntax errors to best practice violations, making it essential for any AL development.

PerTenantExtensionCop (D): This analyzer is specifically designed for extensions that are intended to be installed for individual tenants. It includes rules that ensure the extension does not interfere with the per-tenant customizations and adheres to the guidelines for extensions that can be safely installed and uninstalled without affecting the underlying application.

AppSourceCop (E): This analyzer is tailored for extensions that are intended for publication on Microsoft AppSource. It enforces additional rules that are specific to AppSource submissions, such as checking for the use of reserved object ranges and ensuring that all prerequisite dependencies are correctly declared. This is crucial for ensuring that your app meets all the requirements for listing on AppSource.

By activating these three analyzers, developers can ensure their app adheres to the standards required for AppSource, as well as maintain high code quality and compatibility with Business Central.

You are customizing Business Central using Visual Studio Code and JSON files for configuration.

You plan to:

Open page 21 after publishing.

Enable debugging.

Disable the capability to download the source code.

Which configurations should you add?

The options involve two primary JSON files: launch.json and app.json, and configuration tags like startupObjectId and resourceExposurePolicy.

Developed by using any coding language: Connect app

Developed by using AL language in Visual Studio Code: Add-on app

In Microsoft Dynamics 365 Business Central, there are distinct types of applications that can be developed: Connect apps and Add-on apps. Each has its own development language requirements:

Connect apps:

Connect apps are designed to connect Business Central with external services or applications. They are often developed using a variety of programming languages, not limited to the AL language, and can be hosted outside of the Business Central environment. Therefore, when a description states that the app is developed using any coding language, it generally refers to a Connect app. This type of app integrates with Business Central through APIs and web services.

Add-on apps:

Add-on apps are built to extend the functionality of Business Central within the application itself. These are developed using the AL language, which is the programming language for Business Central, and they are created and managed within the Visual Studio Code environment with the AL Language extension. An Add-on app is typically a Business Central extension that is directly installed into the Business Central environment.

The language and environment used for developing these apps are key differentiators between Connect apps and Add-on apps.

When creating a page with the PageType property set to RoleCenter in Microsoft Dynamics 365 Business Central, it's essential to organize the functionalities and actions in a manner that enhances user experience and efficiency. The best practice is to define actions in the area (reporting) before actions in the area (creation) (A). This organization allows users to access reporting and analytical features quickly, which are commonly used in Role Centers for overview and insight purposes, before moving on to creation or transactional tasks. This logical flow aligns with typical user workflows, where analysis and review precede the creation of new records or transactions. The other options, such as defining the navigation menu in the area(processing) (B), defining the navigation bar in the area (embedding) (C), or adding a source table on the Role Center page (D), do not directly address the need to add functionalities to the Role Center page in a user-friendly manner.

In line 12, declare "Job Task" as a variable. = NO

Add the property FieldClass = FlowField; for field 3. = YES

Add the property FieldClass = FlowFilter; for field 3. = NO

In line 23, assign the "User Setup" table to a field. = YES

For "In line 12, declare 'Job Task' as a variable": In the AL code provided, the "Job Task" appears to be part of a CalcFormula of a FlowField, which means it references a table and not a variable. The "Job Task" does not need to be declared as a variable because it is used to reference a table in a CalcFormula expression.

For "Add the property FieldClass = FlowField; for field 3": The line of code CalcFormula = sum("Job Task"."Recognized Sales Amount" where("Job No." = field("No."))); indicates that this field is calculated from other table data, which is the definition of a FlowField. Therefore, adding the property FieldClass = FlowField; is necessary for the field to function correctly.

For "Add the property FieldClass = FlowFilter; for field 3": FlowFilters are used to filter data based on the value in a flow field. Since field 3 is using a CalcFormula to sum values, it is a FlowField and not a FlowFilter. Therefore, this statement is not correct.

For "In line 23, assign the 'User Setup' table to a field": The line TableRelation = "User Setup"; suggests that the "Project Manager" field has a relation to the "User Setup" table, which is a method of assigning a table to a field to ensure that the values in "Project Manager" correspond to values in the "User Setup" table. Hence, this statement is true.

When updating the base application table using a table extension in Microsoft Dynamics 365 Business Central, certain properties of table fields can be modified to meet new requirements, such as regulatory changes. The DecimalPlaces property (B) is one such property that can be adjusted in a table extension. This property determines the number of decimal places that are displayed and stored for decimal fields in the table. Adjusting the DecimalPlaces property can be particularly useful when dealing with financial data and tax calculations that require precision to meet new tax tiers set by a regulator. It's important to note that not all properties can be modified in a table extension; for example, the CalcFormula property (A) cannot be changed as it affects how the field's value is calculated, which could have significant implications on the base application's logic.

In a single-tenant deployment architecture of Business Central on-premises, the following characteristics describe how the data is stored and how the Business Central Server is configured:

The application and the business data are stored in the same database (B): In a single-tenant architecture, each tenant (which typically corresponds to a single customer) has its own dedicated database. This database contains both the application objects (such as pages, reports, codeunits, etc.) and the business data (such as customer, vendor, and transaction records). This setup ensures that each tenant's data is isolated and can be managed independently.

The application and business data are stored in separate databases (D): While (B) is a characteristic of a single-tenant deployment, it's important to clarify that in some configurations, the application objects can be stored in a separate database from the business data. This approach can be used for easier maintenance and upgrades of the application code without affecting the business data. However, each tenant still has its own set of databases, maintaining the single-tenancy model.

The other options provided do not accurately describe a single-tenant architecture:

Each customer has their own Business Central Server (A): This statement might be misleading. In a single-tenant deployment, while each customer has their own database, they do not necessarily have their own Business Central Server instance. Multiple databases (tenants) can be hosted on a single server instance, although they are not shared across customers.

Multiple customers share a single Business Central Server (C) and Multiple customers share multiple Business Central Server instances (E): These options describe a multi-tenant architecture rather than a single-tenant one. In a multi-tenant setup, multiple customers (tenants) can share the same server instance and even the same application database, with data isolation ensured at the application level.

To meet the XMLport configuration requirements:

Link the child table to its parent: Use the OnAfterGetRecord trigger.

Display a confirmation message after the XMLport runs: Use the OnPostXMLPort trigger.

In Business Central, when you are developing an XMLport for data export, triggers are used to perform actions at different stages of the XMLport's operation:

OnAfterGetRecord Trigger:This trigger fires after a record is retrieved from the database but before it is processed for output in the XMLport. It is the ideal place to link child table records to their parent because you have access to the current record that can be used to set filters or modify data in the child table before it is written to the XML file.

OnPostXMLPort Trigger:This trigger fires after the XMLport has finished processing all records. It is the correct place to display a confirmation message because it ensures that the message will appear after the entire XMLport operation is complete. Here, you can use application-specific functions to show the message, such as MESSAGE function in AL code.

By placing the appropriate triggers in these positions, you can ensure that the XMLport will link the child records to their parent records during the data export process and will notify the user with a confirmation message once the operation is successfully completed.

Here’s the process to follow in the correct sequence:

In Visual Studio Code, locate the Ext Standard Sales - Invoice report extension from your application.

The first step is to locate the specific extension you're working with so you can modify or inspect its code.

Search where the NewTotalVATBaseLCY variable is being calculated and set a breakpoint on the line.

To debug the issue, you need to place a breakpoint on the line where the NewTotalVATBaseLCY is calculated.

Start debugging.

Once the breakpoint is set, you begin the debugging process to examine the values and code execution.

Use the step-over functionality.

After starting the debugging, you will use the step-over functionality to move through the code line by line and observe the values of the variables.

To create a query that assigns vendors to items in Business Central, use the following code blocks in sequence:

dataitem(Vendor; Vendor)

dataitem(Item; Item)

DataItemLink = "Vendor No." = Item.Vendor_No;

Creating a query:In Business Central, a query object is used to combine data from multiple tables. You start by specifying each table as a data item. In this case, you would start with the Vendor table and then the Item table. After specifying the data items, you need to link them together. The DataItemLink property is used to establish a relationship between two data items based on a common field. Here, you are linking the Vendor and Item tables on the "Vendor No." field, which is present in both tables. This link ensures that the query will return a dataset that includes related records from both tables based on the vendor number. The order of the code blocks ensures the logical flow and relationships between tables as required for the query.

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 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 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).

 Verbosity::Critical: This ensures that the telemetry logs the failure as a critical event.

 DataClassification::CustomerContent: This helps classify the error as related to customer data.

 TelemetryScope::All: This ensures that the error is visible across all relevant telemetry scopes, making it easier to monitor the issue in real-time.

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.

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.

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.

Instructions to use for Incident Date and Status fields:

The correct instruction is "Incident Date" := Workdate(); "Status" := Status::Open;. This ensures that when a new record is created, the Incident Date is set to the current work date, and the Status field is initialized to 'Open'. This is essential for ensuring that the incident data is always timestamped and correctly marked upon creation.

Trigger to introduce the function:

The correct trigger is Trigger OnModify. This trigger ensures that when a record is modified, such as when an update to the status is made (e.g., from Open to Closed), the necessary logic will be executed to handle the update of fields like Incident Date and Status.

Step-by-Step References:

Workdate Function in AL

Triggers in AL

https://api.businesscentral.dynamics.com/v2.6/myTenant/myEnvironment/api/alpine/integration/rooms

 Design pattern for the setup table:

The correct selection here is Adapter. The Adapter design pattern is commonly used when you need to handle integration points or create a setup table that acts as an intermediary for data manipulation, which fits the requirement for the configuration of the non-conformity functionality.

 Data type of the primary key field:

The correct data type is Code. In Business Central, when creating a table with a primary key field, the Code data type is typically used for fields such as document numbers, codes, and identifiers. For a setup table, a Code field is appropriate for keys like "No." series or setup identifiers.

 Property required to prevent users from adding records:

The correct property is InitValue. This property is used to set initial values for fields and can be configured in such a way that users are prevented from adding records directly, typically enforcing control over record creation and editing in configuration scenarios.

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;

}

field(3; "Receipt No."; Code[20])

{

DataClassification = CustomerContent;

TableRelation = "Purch. Rcpt. Header"."No." where ("Buy-from Vendor No." = field("Vendor No."));

}

Field Declaration:

The field(3; "Receipt No."; Code[20]) part defines the field in the table with ID 3 and type Code with a length of 20. This field will hold the receipt number.

DataClassification:

CustomerContent is selected for the DataClassification property, which categorizes the data for privacy and compliance management. This aligns with Business Central's recommendations for handling sensitive data in customer-related tables.

TableRelation Property:

The TableRelation property links the "Receipt No." field to another table, which in this case is the "Purch. Rcpt. Header" table. This ensures that only valid receipt numbers from the Purchase Receipt Header table can be selected or entered in this field.

Relation Filter:

The filter condition is applied using the where clause. It ensures that the Receipt No. is only from the Purchase Receipt Header records where the "Buy-from Vendor No." matches the "Vendor No." of the current record.

The condition field("Vendor No.") is selected from the drop-down as shown in the image. This links the vendor information in the non-conformity table to the receipt in the Purchase Receipt Header table.

By linking the "Vendor No." fields, you ensure that only receipt numbers from the correct vendor are available, which improves data consistency and reduces errors during data entry.

References to AL Language:

The TableRelation property is frequently used to create references between tables in Business Central. In this case, the correct relationship between the "Purch. Rcpt. Header" and the Non-conformity table is established using the TableRelation and filter.

Reference Documentation:

AL TableRelation Property

AL Field Syntax

Read Scale-Out:

Read scale-out is a feature in Business Central that allows you to improve performance by distributing read-only queries (such as the ones from the ticketAPI) across multiple read replicas in the cloud database. This reduces the load on the primary database and helps improve the response time for read-intensive operations, like analyzing POS data through the ticketAPI.

Data Access Intent - ReadOnly:

When enabling read scale-out, you can configure the DataAccessIntent property of APIs to be ReadOnly. This directs the system to use read replicas to handle read-only queries, which enhances performance by offloading such queries from the primary database.

Why Not Other Options?

Option A (ODataReadonlyGetEnabled): This parameter is unrelated to read scale-out and primarily affects OData services behavior, not API performance tuning.

Option B (AccessByPermission): Setting the permission to Read does not directly affect the performance. It only controls access based on user permissions.

Option D (DataAccessIntent ReadOnly): While setting this property to ReadOnly helps in read-only operations, enabling read scale-out (option C) ensures the underlying infrastructure is optimized to handle such read operations, which is the fundamental action required.

Reference Documentation:

Read Scale-Out in Business Central

Data Access Intent in AL