Jared Westover looks at key constraints:
In late 2024, I noticed a comment on the Microsoft Learn site stating that foreign keys could improve query performance on tables in a Fabric warehouse. That claim immediately caught my attention. I wanted to answer a simple question: Do relationships help, hurt, or have no effect when added to tables in a Fabric warehouse?
Let’s get more specific—do foreign keys improve query performance when reading data (not loading)? In other words, do they make queries run faster?
Sadly, the answer is not as promising as with SQL Server. But this also makes sense considering the distributed nature of Fabric data warehouses.