Sometimes called an OLAP model, this Power BI and Fabric layer defines the measures, hierarchies, tables and relationships that reports and dashboards query; star schema design is the usual pattern.
Also called formerly dataset, Dataset, OLAP cube, Power BI dataset.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Semantic model in context, with comparison tables and the common traps.
Terms in this definition
- OLAP
Online analytical processing, models built for aggregating data and slicing it in different ways; Azure Analysis Services is one example.
- Power BI
Microsoft's analytics and reporting service. It reaches data held on-premises through the on-premises data gateway.
- Star schema
A model for analytics named after its diagram's shape: dimension tables describing the data surround, and link to, one central fact table holding the measures.
- Pattern
A reusable answer to a recurring problem that places building blocks in context, explaining when, how and why to apply them and what compromises are involved.
Related terms
- ADOMD
The .NET client library for Analysis Services that tools use to run queries against a semantic model over the XMLA endpoint. Administrative work is left to its sibling library, AMO.
- Aggregations
Summary queries over a large DirectQuery table can be answered from memory instead of the source thanks to this semantic model feature: it keeps a concealed summary table cached and sends qualifying queries there, while anything needing fine detail still goes back to the source.
- ALM Toolkit
An open-source, no-cost utility for comparing Power BI semantic model schemas. Because it can release just the metadata changes you pick through the XMLA endpoint, a model that's already published keeps both its data and its incremental refresh partitions.
- Analysis Services
VertiPaq, Microsoft's in-memory analytics engine, sits underneath every Power BI semantic model and is likewise available as Azure Analysis Services or SQL Server Analysis Services. Tools connect to it over XMLA, using its client libraries.
- Analytical data processing
Working with big sets of historical data or business measures, mostly reading rather than writing, typically after loading them into a lake, warehouse or lakehouse and on into a semantic model for reporting. It contrasts with OLTP, or transactional, workloads.
- Analyze in Excel
A way to explore a published semantic model from Excel: the service produces a workbook connected live to the model, so PivotTables send MDX queries to it. Users need Build permission on the model.
- Best Practice Analyzer
A prebuilt notebook you can launch for any semantic model in the Power BI service. It scores your design on over 60 checks covering speed, DAX quality, avoiding errors, upkeep and formatting, and running it calls for Build rights plus a Fabric-backed workspace.
- Build permission
Allows a person to make new things on top of a semantic model: reports, Analyze in Excel sessions or XMLA endpoint queries, for example. Anyone with the Contributor workspace role or higher gets it without being granted it separately.