1.1.1. The Power BI Ecosystem: Desktop, Service, and Fabric
💡 First Principle: Authoring and consuming are different jobs with different needs. Authors need a powerful, local workbench where they can experiment freely; consumers need a secure, always-available place to view, share, and refresh results. Power BI splits these jobs across tools, and exam questions often hinge on where a task is performed.
Power BI Desktop is the free Windows authoring tool. It contains the Power Query Editor (connect and transform), the Model view (relationships and properties), the Report view (visuals), the Table view (data inspection), the DAX query view (write and test DAX queries), and the TMDL view (script the model as code). Anything structural, such as defining relationships, writing measures, defining row-level security roles, or creating a theme, starts here.
The Power BI service (app.powerbi.com) is the cloud platform where content is published into workspaces. Here you schedule refresh, configure gateways, assign workspace roles, publish apps, create dashboards, set subscriptions and alerts, endorse content, and assign people to row-level security roles. The service also offers web authoring for reports and, for some sources, semantic models.
Microsoft Fabric is the broader analytics platform that the Power BI service now lives inside. Fabric adds lakehouses, warehouses, notebooks, and pipelines, all storing data in OneLake. For the PL-300, Fabric matters in three places: it is a data source (lakehouse and warehouse tables), it enables the Direct Lake storage mode, and its paid capacities (F SKUs, plus legacy Power BI Premium P SKUs while they last) are required for features such as Direct Lake and Copilot.
| Tool | Primary job | Typical exam tasks |
|---|---|---|
| Power BI Desktop | Author models and reports | Power Query transformations, relationships, DAX, RLS role definitions, themes, bookmarks |
| Power BI service | Share, refresh, govern | Workspaces, apps, refresh schedules, gateways, RLS membership, endorsement, subscriptions |
| Power BI Report Builder | Author paginated reports | Pixel-perfect, multi-page, printable operational reports (.rdl) |
| Power BI Mobile | Consume on phones and tablets | Viewing mobile-optimized layouts, receiving alerts |
| Microsoft Fabric | Unified data platform | Lakehouse/warehouse sources, Direct Lake, capacity for Copilot |
⚠️ Exam Trap: Row-level security has two halves in two tools. You define roles and their DAX filters in Desktop, but you assign users or groups to those roles in the service. A stem that asks where to add members to a role is pointing at the semantic model's Security page in the service, not at Desktop.
Reflection Question: A colleague says, "I'll just email everyone the .pbix file." Name two capabilities the organization loses by skipping the service, and explain why each one depends on the content living in a workspace.
