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.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Analysis Services in context, with comparison tables and the common traps.
Terms in this definition
- VertiPaq
The in-memory engine behind Power BI; Direct Lake pulls Delta and Parquet data into it.
- Power BI
Microsoft's analytics and reporting service. It reaches data held on-premises through the on-premises data gateway.
- Semantic model
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.
- Azure Analysis Services
Azure service hosting tabular OLAP models for large numbers of Power BI and Excel users; semantic models in Power BI Premium are its modern counterpart.
- SSAS
Hosts multidimensional and tabular models in Microsoft's own on-premises analysis engine. Through Connect live, Power BI queries it directly, signing in with each person's Windows account details.
- CONNECT
In SQL Server, the right to open a connection to a database. Fabric's equivalent is Read permission on an item, which allows connecting to a warehouse or SQL endpoint but not querying anything in it.
- OVER
Gives a T-SQL window function its window: PARTITION BY, ORDER BY and, if wanted, a ROWS or RANGE frame. Rankings and running totals can then be worked out while every row is kept.
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.
- AMO
A .NET client library that SSMS and Visual Studio use to administer Analysis Services servers and define their objects; for tabular models, TOM (the Tabular Object Model) builds on top of it.
- DAX
Short for Data Analysis Expressions, the formula language you write measures, calculated columns and row-level security rules in, within tabular semantic models in Power BI, Excel Power Pivot or Analysis Services.
- DMV
Dynamic management views expose what a server is doing right now. Fabric warehouses offer sys.dm_exec_requests and similar views for connections, sessions and active requests; through XMLA, semantic models provide Analysis Services DMVs, except ones requiring server admin rights.
- MDX
The query language that clients like Excel PivotTables, including Analyze in Excel, send to Analysis Services models. Because MDX can't aggregate columns implicitly, such clients rely on explicit measures.
- MSOLAP
Excel, SSMS and similar tools reach semantic models through the XMLA endpoint using Microsoft's native Analysis Services client library (alongside ADOMD.NET and AMO/TOM). Microsoft apps install and update it automatically.
- SSDT
Enterprise tabular models are often built using Visual Studio plus its Analysis Services projects add-on. Publishing such a project into Power BI needs add-on version 2.9.14+, compatibility 1500+, and XMLA read-write switched on.