DAX parameter-naming conventions
Parameter names are standardized in DAX reference to facilitate the usage and understanding of the functions.
Parameter names
| Parameter | Description |
|---|---|
| expression | Any DAX expression that returns a single scalar value, where the expression is to be evaluated multiple times (for each row/context). |
| value | Any DAX expression that returns a single scalar value where the expression is to be evaluated exactly once before all other operations. |
| table | Any DAX expression that returns a table of data. |
| tableName | The name of an existing table using standard DAX syntax. It cannot be an expression. |
| columnName | The name of an existing column using standard DAX syntax, usually fully qualified. It cannot be an expression. |
| name | A string constant that will be used to provide the name of a new object. |
| order | An enumeration used to determine the sort order. |
| ties | An enumeration used to determine the handling of tie values. |
| type | An enumeration used to determine the data type for PathItem and PathItemReverse. |
Prefixing parameter names or using the prefix only
| Parameter | Description |
|---|---|
| prefixing | Parameter names may be further qualified with a prefix that is descriptive of how the argument is used and to avoid ambiguous reading of the parameters. For example: Result_ColumnName – Refers to an existing column used to get the result values in the LOOKUPVALUE() function. Search_ColumnName – Refers to an existing column used to search for a value in the LOOKUPVALUE() function. |
| omitting | Parameter names will be omitted if the prefix is clear enough to describe the parameter. For example, instead of having the following syntax DATE (Year_Value, Month_Value, Day_Value) it is clearer for the user to read DATE (Year, Month, Day); repeating three times the suffix value does not add anything to a better comprehension of the function and it clutters the reading unnecessarily. However, if the prefixed parameter is Year_columnName then the parameter name and the prefix will stay to make sure the user understands that the parameter requires a reference to an existing column of Years. |
