Row context

In the Ultra Transcenders books

PL-300

Each book explains Row context in context, with comparison tables and the common traps.

Terms in this definition

• LIKE

  Compares strings with a pattern that can contain the % and _ wildcards. Because it only understands character patterns, searching big volumes of text this way is much slower than using full-text search.

• SUMX

  Iterates over each table row, evaluating an expression, then totals those results; text, logical values and blanks don't count.

• 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.

• Filter context

  Whenever DAX evaluates an expression, each column is limited to certain values by slicers, report filters, a visual's rows and columns, relationships and any filters coded in formulas. Measures always calculate under these limits; row context, by contrast, means the current row.

Related terms

• CALCULATE

  A DAX function that computes an expression after changing the filter context with filter modifiers, Boolean filters or table filters. Called with no filters, it still turns any row context into filter context, which is known as context transition.

• context transition

  What CALCULATE does to row context: it converts it into an equivalent filter context. You need it for aggregating expressions inside iterators or calculated columns, and referring to a model measure triggers it implicitly.

• Iterator

  A DAX function like SUMX that steps through a table one row at a time, evaluating an expression in row context, and then aggregates what it gets.

• RELATED

  Fetches a column value from the lookup table, that is the one side of a many-to-one relationship, for whichever row is being evaluated. It therefore needs to run inside an iterator or a calculated column, where row context exists.