How many different values a column holds. Columns with many distinct values compress badly in Import mode, so cutting them down makes the model smaller; this is separate from the cardinality of a relationship, such as one-to-many.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Cardinality in context, with comparison tables and the common traps.
Terms in this definition
- VALUES
Returns in DAX the distinct column values, or table rows, still visible after filters are applied, sometimes with an extra blank entry. CALCULATE often takes the result as a table filter.
- Import mode
Copies data into the model's in-memory cache, so a refresh is needed before changes appear. It is Power BI's most used storage mode and what a new Power BI Desktop solution starts with.
Related terms
- ASSUME_FIXED_MAX_SELECTIVITY_FOR_REGEXP
A query hint for SQL Server 2025 and Azure SQL Database that gives
REGEXP_LIKEa fixed, higher selectivity, for cases where the normal cardinality estimate comes out too low. - ASSUME_FIXED_MIN_SELECTIVITY_FOR_REGEXP
A query hint for SQL Server 2025 and Azure SQL Database that gives
REGEXP_LIKEa fixed, lower selectivity, for cases where the normal cardinality estimate comes out too high. - Automatic statistics
When queries run against the Fabric Data Warehouse or the SQL analytics endpoint, the engine creates statistics (histograms, cardinality and average column length) on columns used for filtering, joining, grouping, sorting or DISTINCT. The histogram objects are named with a
_WA_Sys_prefix. - Model relationship
A connection between columns in two semantic model tables, with a cardinality and a cross-filter direction, that lets filters flow from one table to the other. It does not check referential integrity.