MB-820: Dynamics 365 Business Central Developer Practice Exam

What the MB-820 exam covers

• Describe Business Central95 questions
• Install, develop, and deploy for Business Central95 questions
• Develop by using AL objects285 questions
• Develop by using AL127 questions
• Work with development tools94 questions
• Integrate Business Central with other applications95 questions

Free MB-820 sample questions

A sample of 10 questions with answers and explanations. Sign up free to practice all 791.

1. Question 1Describe Business Central

   Which component of the Business Central architecture executes AL code and enforces business logic?

   • AThe Business Central Server, which hosts the service tierCorrect
   • BThe Business Central Web Client, which renders pages and handles user interaction in a browser
   • CThe SQL Server database, which stores table data and executes the queries the client issues
   • DThe Business Central Administration Center, which manages environments and update schedules
   ✓ Correct answer: A

   Business Central is a three-tier application. The client renders the UI, SQL Server persists data, and the Business Central Server sits between them as the service tier, compiling and executing AL objects, enforcing permissions and managing the data cache. When you publish an extension, its compiled .app is deployed to that server tier, which is why an AL runtime error surfaces from the server rather than the browser.

   Why the other options are wrong

   • BThe Web Client renders pages and handles interaction, but the AL itself runs on the server tier.
   • CSQL Server stores the table data and executes queries; it does not execute AL business logic.
   • DThe Administration Center manages environments and updates rather than running any AL code.
2. Question 2Describe Business Central

   Which best describes what a developer sees when opening the base application source in Visual Studio Code?

   • ARead-only reference source downloaded to inspect behaviour and find event publishersCorrect
   • BAn editable copy that, once changed and published, replaces the base application in the environment
   • CNothing, because base application source is never available to partners in any form
   • DOnly object headers, since the procedure bodies are stripped from what partners can obtain
   ✓ Correct answer: A

   Microsoft makes base application source available for reference so developers can understand behaviour and locate the events they need to subscribe to. It is not a starting point for modification: an extension attaches through supported extension points, and changes to the reference copy have no effect on the environment.

   Why the other options are wrong

   • BAn edited copy cannot replace the base application; the extension model prevents that.
   • CReference source is available to partners rather than being withheld entirely.
   • DProcedure bodies are present in the reference source rather than stripped out.
3. Question 3Install, develop, and deploy for Business Central

   Which describes what happens to job queue entries when an environment is copied?

   • AThey are copied but are not started automatically in the new environmentCorrect
   • BThey are copied and begin running immediately in the new environment
   • CThey are excluded from the copy and must be recreated from scratch
   • DThey are copied and their next run time is set to the moment of the copy
   ✓ Correct answer: A

   Copying an environment brings the job queue entries across but leaves them inactive, which prevents a sandbox from immediately sending emails, calling external services or posting documents as if it were production. Reactivating deliberately is part of preparing a copied environment for use.

   Why the other options are wrong

   • BCopied entries do not begin running immediately; the platform leaves them inactive.
   • CThe entries are copied rather than excluded; they simply do not start.
   • DNo next run time is scheduled at the moment of the copy, because the entries are not started.
4. Question 4Develop by using AL objects

   Which describes the purpose of the CardPageId property on a list page?

   • AIt names the card page opened when a user drills into a list rowCorrect
   • BIt names the page shown as a fact box beside the list
   • CIt names the page used when the list's records are printed
   • DIt names the page that replaces the list for users on mobile devices
   ✓ Correct answer: A

   CardPageId connects a list to the card that shows one of its records in full. Setting it gives users the expected behaviour when they open a row, and it also tells the platform which page to use when a new record is created from the list. Without it, opening a row leaves the user on the list with no detail view.

   Why the other options are wrong

   • BFact boxes are declared as parts in the page layout rather than through this property.
   • CPrinting is handled by reports rather than by a designated card page.
   • DMobile rendering uses the same page objects rather than substituting a different page.
5. Question 5Develop by using AL objectsSelect all that apply

   Which TWO are appropriate uses of an XMLport? (Choose TWO)

   • AImporting a supplier's price list supplied as a CSV fileCorrect
   • BExporting posted entries as XML for an external systemCorrect
   • CExposing live data for a Power BI report to query
   • DRendering a customer invoice for printing and emailing
   ✓ Correct answer: A, B

   XMLports move data between Business Central and files in either direction, so both a CSV import and an XML export sit squarely in their remit. Live querying belongs to OData through a page or query, and rendering a printable invoice belongs to a report. Both file cases benefit from the schema mapping and per-record triggers an XMLport provides.

   Why the other options are wrong

   • CLive data for a Power BI report is exposed through OData rather than an XMLport.
   • DRendering an invoice for printing is a report's job rather than an XMLport's.
6. Question 6Develop by using AL objects

   Which AL object type declares the rights an extension grants over its own objects?

   • ApermissionsetCorrect
   • Bentitlement, which maps licence types to the permission sets they receive
   • Cprofile, which binds a role to a Role Center and page customizations
   • Dquery, which joins tables and returns a read-only dataset to callers
   ✓ Correct answer: A

   The permissionset object lists objects and the rights granted over them, and administrators assign it to users. Shipping one with an extension is essential, because base application permission sets know nothing about the objects an extension defines and users would otherwise hit access errors.

   Why the other options are wrong

   • BAn entitlement maps licence types to permission sets rather than declaring the rights.
   • CA profile shapes the interface rather than granting object rights.
   • DA query returns data rather than declaring permissions.
7. Question 7Develop by using AL

   Which AL type represents a collection whose members are accessed by key?

   • ADictionary, holding key and value pairsCorrect
   • BList, holding elements accessed by position
   • CArray, holding a fixed number of elements
   • DTextBuilder, holding text that is appended to
   ✓ Correct answer: A

   A Dictionary maps keys to values with fast lookup, which suits a cache or a translation from one code system to another. A List is ordered and accessed positionally, and an Array is a fixed-size sequence, so the choice follows from how the data will be reached.

   Why the other options are wrong

   • BA List is accessed by position rather than by key.
   • CAn Array holds a fixed number of elements accessed by index.
   • DTextBuilder accumulates text rather than holding a keyed collection.
8. Question 8Develop by using AL

   Which describes the correct way to implement steps within a NavigatePage?

   • AGroups shown and hidden as the user moves through the sequenceCorrect
   • BSeparate page objects the wizard opens one after another
   • CA repeater whose rows represent the individual steps
   • DActions that each open a different configuration page
   ✓ Correct answer: A

   A wizard is one page whose step groups are made visible in turn, with the Next and Back actions changing which is shown and updating the page. Keeping everything in one object means the values collected in earlier steps are available in later ones without any passing between pages.

   Why the other options are wrong

   • BSeparate pages lose the collected values between steps and break the wizard's continuity.
   • CA repeater lists records rather than presenting sequential steps.
   • DActions opening separate pages abandon the guided sequence.
9. Question 9Work with development tools

   Which is the appropriate way to measure whether a performance improvement worked?

   • ACompare the operation's telemetry before and after the change in productionCorrect
   • BTime the operation once in a sandbox before and after
   • CAsk users whether the application feels faster
   • DRely on the code review's judgement that the change is faster
   ✓ Correct answer: A

   Production carries the data volumes, concurrency and hardware that determine real performance, and telemetry measures the operation across many runs rather than one. That combination is what distinguishes a genuine improvement from one that only appears in a small sandbox.

   Why the other options are wrong

   • BA single sandbox timing lacks production's volume, concurrency and variance.
   • CAsking users whether the application feels faster cannot quantify the change.
   • DA reviewer's judgement is a hypothesis rather than a measurement.
10. Question 10Integrate Business Central with other applications

    Which is the correct way for an API caller to update only some fields of a record?

    • ASend a partial update, which changes only the supplied propertiesCorrect
    • BSend the whole record, since partial updates are not supported
    • CDelete the record and create a replacement with the new values
    • DInvoke a bound action for each field that must change
    ✓ Correct answer: A

    The API supports updating a subset of properties, which is what an integration usually wants: change the status without resending everything else. That also avoids the caller overwriting fields another process changed between their read and their write. Combining a partial update with the entity tag gives both a small payload and concurrency safety.

    Why the other options are wrong

    • BPartial updates are supported and are the normal way to change a few fields.
    • CDelete and recreate loses history and any values the caller did not know about.
    • DA bound action per field would be an odd and unnecessary API design.

Who this MB-820 practice exam is for

This practice set is for anyone preparing for the MB-820: Dynamics 365 Business Central Developer exam at the intermediate level - from first-time candidates building a foundation to experienced Microsoft practitioners doing a final review before test day. If you learn best by working through realistic questions and reading why each answer is right or wrong, it is built for you.

How to use this MB-820 practice exam

1. Start with the free sample questions above to gauge your current baseline.
2. Read the full explanation on every question, including why each wrong option is wrong.
3. Track your weak domains and focus your study where you are losing the most marks.
4. Once you are scoring consistently well, take a timed, full-length mock exam.
5. Use your readiness score to decide when you are ready to book the real MB-820 exam.

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