Power BI is packed with features that make data modeling easier, but beneath the surface, every dataset follows a structured format. That’s where Tabular Model Definition Language (TMDL) View comes in. This relatively new feature allows users to view and edit the structure of their Power BI models in a human-readable script format. But why should you care about it? Who can use it? And how can it enhance your workflow? Let’s dive in.
What Is TMDL View?
TMDL (Tabular Model Definition Language) is a structured scripting language that defines the objects inside a Power BI dataset. Think of it as the blueprint of your data model, where everything—tables, relationships, measures, hierarchies—is represented in text form. With TMDL View, Power BI now allows users to inspect and modify their data models directly via a script-based approach.
In simpler terms, if you’ve ever wished to see behind the scenes of a Power BI model without diving into external tools like Tabular Editor, TMDL View is your answer.
Why Use TMDL View?
1. Greater Transparency in Data Modeling
TMDL View shows the whole model as a script, simplifying the detection of inconsistencies, dependencies, or missing elements in Power BI Desktop.
2. Version Control and Collaboration
Since TMDL is text-based, you can store it in Git. This lets teams track changes, compare model versions, and collaborate efficiently without breaking the dataset. Read what Rui Romano , Principal Program Manager at Microsoft, has to say about Git integration.
3. Faster Model Editing
Manually adjusting table properties in Power BI Desktop is tedious. TMDL lets you rename columns, modify relationships, and change data types quickly from one script file.
4. Bulk Changing
Need to make the same change across multiple tables? Instead of clicking through the UI, you can update the TMDL file directly, making bulk edits faster and more efficient
Who Can Use TMDL View?
Do You Need to Be a Pro Developer?
A strong understanding of Power BI data modeling concepts is essential. TMDL View isn’t a no-code feature like Power BI’s drag-and-drop interface; it requires familiarity with dataset building.
Can Low-Code or No-Code Users Work with TMDL?
Power BI’s TMDL might seem daunting at first, especially if you rely on visual tools. But if you’re familiar with DAX, M, or JSON configurations (like Tabular Editor or Power BI REST API), it’s easier to understand. For low-code users, learning TMDL can improve model management efficiency.
Is It Hard to Learn?
The difficulty depends on your experience with Power BI:
- If you’re familiar with Power BI modeling, picking up TMDL will be straightforward since it reflects the concepts you already know.
- If you’re new to scripting, there might be an initial learning curve, but you don’t need to be a programmer. Reading and modifying structured text files are the main skill required.
- If you want to master it, dedicate some time to experimenting. Start by dragging a table into TMDL View, analyzing the output, and making small edits to see the impact.
For users who manage multiple datasets or collaborate in teams, investing in learning TMDL can be highly beneficial. Get an overview of Tabular Model Definition Language here.
How to Get Started with TMDL View
1. Enable TMDL in Power BI Desktop
- Open Power BI Desktop (ensure you have the latest version).
- Go to File > Options and Settings > Options.
- Under Preview Features, enable TMDL View.
- Restart Power BI.
2. Open the TMDL View
- Once enabled, navigate to the Model View.
- Drag and drop a table into the TMDL canvas.
- You’ll now see the corresponding TMDL script, representing the dataset’s structure.
3. Modify the Script
- Try renaming a table or adding a new measure directly in the script.
Notice that it is giving suggestion and a way to autocomplete just like other programming tools.
Final measure looks like below,
- Save the changes and observe how the model updates in Power BI.
Let’s check UI how the measure is generated and if it is working.
Notice it is same as how we write measures in the Power BI Desktop but this time, we did it using the TMDL view.
Some Possible Scenarios and Solutions: When to Use TMDL
Scenario 1: Bulk Editing Table and Column Properties
Problem: You need to rename multiple columns across different tables.
Solution: Instead of clicking through each column manually, modify the TMDL script to apply changes instantly.
Scenario 2: Managing Large-Scale Power BI Deployments
Problem: Your organization has multiple datasets that need frequent updates.
Solution: Use TMDL to automate model updates via scripts, reducing manual effort.
Scenario 3: Version Control for Power BI Models
Problem: Your team struggles to track changes in the data model.
Solution: Store TMDL scripts in a version control system like Git to compare different versions and collaborate more effectively.
See more relevant scenarios here.
Limitations and Considerations
While TMDL View is a powerful feature, it’s important to keep these limitations in mind:
- Still in Preview – TMDL editing is a preview feature, meaning it may change or have some bugs.
- Not a Full Replacement for UI – Some operations are still easier to perform through the Power BI interface, especially for visual learners.
- Learning Curve for Non-Technical Users – If you’re not familiar with structured scripting, it may take time to adjust.
- No Direct Execution – Unlike DAX or Power Query (M), TMDL is not an executable script. It defines model structure but doesn’t perform transformations or calculations.
- Feature Gaps: Some advanced modeling features may not yet be fully supported in TMDL. See Limitations and Considerations.
Final Thoughts
TMDL View in Power BI introduces a new way to interact with data models, making it easier to manage, edit, and collaborate on complex datasets. While it’s best suited for advanced users, those willing to invest time in learning it can gain greater control, efficiency, and scalability in their Power BI workflows. Whether you’re a seasoned developer or a Power BI power user looking to streamline your data modeling process, TMDL is a feature worth exploring.
If you haven’t tried it yet, open Power BI, enable the feature, and start experimenting—you might just find it to be a game-changer! Read how Chris Webb has also explored TMDL View, highlighting its impact on developer productivity and model management in Power BI.
