Mastering Data Entities in D365 F&O: Creating a Custom Data Entity from Scratch

 One of the most powerful features in Dynamics 365 Finance and Operations is the Data Management Framework (DMF). Whether you're building integrations, facilitating data migrations, or enabling Excel-based edits — data entities are the cornerstone.

While standard entities cover a wide range of scenarios, there are times when you need a custom entity tailored to your exact business requirement.

Today’s post will walk you through the entire process of building a custom data entity from scratch, using best practices every technical consultant or architect should follow.

When and Why to Build a Custom Data Entity?

Before jumping in, it’s important to ask:

• Does a standard entity already cover the requirement?

• Is the customization aligned with business processes?

• Will the entity be used for inbound, outbound, or dual-directional integrations?

If the answer points to a clear gap, it's time to create your own.

Use Case

Let’s say your client wants to integrate a custom loyalty program with D365 F&O. They’re storing loyalty card data in an external system and want to push it into a custom table named LoyaltyMemberTable.

Step-by-Step: Building a Custom Data Entity : -

1.   Create the Table (If It Doesn't Exist) with the below fields : - 

           

       string CardNumber ,  CustAccount CustomerAccount , TransDate JoinDate , string                                   MembershipLevel

       

2.  Create a New Data Entity

• In Visual Studio, right-click on your project → Add → New Item → Data Entity.

• Name it LoyaltyMemberEntity.

• Set the Primary datasource to LoyaltyMemberTable

• In the properties:

  • Public = Yes (if it should be available for integrations)

  • DataEntityView = Auto

  • IsPublic = Yes

  • IsReadOnly = No

    

3.   Add Fields to the Entity

Select only the necessary fields — avoid exposing internal or irrelevant fields to keep the integration secure and clean.

You can also rename labels or make fields mandatory here.

   

4.   Build and Synchronize

       Once the entity is created:

• Build your solution.

• Sync the database to register the entity in the DMF.

        You’ll now find your new entity under Data Management Workspace > Data Entities.

  

5.    Test It

         Use the Data Management Workspace:

• Try exporting data using your new entity.

• Then test an import with a sample Excel file.

Best Practices to Remember :-

• Use surrogate keys wherever possible to simplify mapping and support system-generated RecIds.

• Limit the number of exposed fields — keep entities lean and focused.

• Add business logic in postLoad/postWrite methods only if necessary.

• For larger datasets, enable incremental export to improve performance.

      

Pro Tip: Extend an Existing Entity When Possible

Before creating a new one, check if an extension of a standard entity can serve your purpose. It keeps things clean and ensures you’re building only what’s needed.

Conclusion

Custom data entities are more than just a way to move data — they’re critical building blocks in a well-architected D365 ecosystem. Whether you're integrating with external systems, enabling Excel-based edits, or facilitating controlled data migrations, knowing how to build a reliable entity is essential.

As a D365 F&O technical consultant or architect, being comfortable with data entities isn’t just a technical skill — it’s a must-have competency for delivering real-world business value.

That's all for now. Please let us know your questions or feedback in comments section !!!!

A Practical Guide to Using Event Handlers in D365 F&O (The Smart Way to Customize)

Customizing standard processes in Dynamics 365 Finance and Operations has evolved significantly. Gone are the days when overlayering was the norm. Today, we work with event handlers - a cleaner, upgrade-safe way to extend standard logic without touching Microsoft’s base code.

In this post, I’ll break down how event handlers work, when to use them, and walk you through a real-world example that illustrates how powerful (and easy) they are to implement.

Why Event Handlers Deserve Your Attention ?

As developers and technical consultants, we’re often tasked with extending standard business logic. Event handlers let us do that without modifying the original codebase. This ensures:

• No conflicts during platform upgrades
• Better code separation for long-term maintenance
• Compliance with Microsoft's One Version policy

Mostly used types of event handlers

Depending on your use case, there are different handler types available:

Event Type	Purpose
Pre-event	Executes before the standard method – ideal for validations
Post-event	Executes after the method – great for additional processing
OnModified, OnValidated	Used for form field-level triggers
DataEventHandlers	Fire during insert/update/delete events on tables

Use Case: Auto-Generating Vendor Codes

Let’s say your client needs vendor records to be assigned a unique code automatically when a new vendor is created. The standard VendTable insert method doesn’t do this out-of-the-box.

Instead of overlayering the base method (which is a no-go in today’s world), we’ll attach a post-event handler.

Let's look at the below example of how to create an event handler :-

class VendTableEventHandler
{
    [PostHandlerFor(tableStr(VendTable), tableMethodStr(VendTable, insert))]
    public static void VendTable_PostInsert(XppPrePostArgs args)
    {
        VendTable vendTable = args.getThis() as VendTable;

        if (!vendTable)
            return;

        vendTable.selectForUpdate(true);
        vendTable.VendCode = VendTableEventHandler::generateVendorCode(vendTable.RecId);
        vendTable.doUpdate();
    }

    private static str generateVendorCode(RecId recId)
    {
        return strFmt("VEND-%1", recId);
    }
}

Now, every time a vendor is created, this handler fires after the insert and assigns a custom vendor code like VEND-123456.

Tips to Keep in Mind

• Keep event logic focused - Don’t clutter handlers with business rules. Move complex logic into helper or service classes.
• Naming matters - Use consistent names like VendTableEventHandler so future developers can easily trace logic.
• Avoid assumptions about execution order - If multiple handlers exist, the order isn’t guaranteed — so design your logic to be independent.

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When to Use Event Handlers vs. Chain of Command

Both are powerful, but they serve different purposes:

Use case	What to use ?
Working with public table/form methods	Event Handler
Modifying protected business logic (services, controllers)	Chain of Command
Handling table-level inserts/updates	DataEventHandler
UI interaction (field validations)	Form event methods

Conclusion

Understanding how and when to use event handlers is essential for any D365 F&O developer or architect. Not only does it keep your codebase cleaner and upgrade-ready, but it also aligns with how Microsoft expects us to extend their platform moving forward. If you’re still relying on overlayering, it’s time to re-think your approach. With just a few lines of code, event handlers give you the flexibility you need — without the headaches that come with platform updates.

That's all for now. Please let us know your questions or feedback in comments section !!!!