Use expressions and parameters
Filter expressions
Define the values a filter should include or exclude—without changing its columns or adding rows.
An expression item evaluates a selected column against a logical operator and value. It can only return the same columns and the same or fewer rows than its input; it is not a join. To combine related tables, use Relation items.
Build an expression itemDirect link to Build an expression item
Select a column and operatorDirect link to Select a column and operator
When you create or edit a filter, add an Expression filter item. Select the column to evaluate, then choose the operator that best represents the condition.
Use a constant or parameterDirect link to Use a constant or parameter
Enter a fixed comparison value for a one-off condition. Use a parameter when the same filter needs a different value in different contexts—for example, when it is used by multiple roles.
Test before savingDirect link to Test before saving
Select Filter to inspect the result in the Result pane. Confirm the expression includes the intended records and excludes the rest, then select Save.
Outcome
The filter returns only rows that satisfy the expression condition.
Choose an operatorDirect link to Choose an operator
| Operator | What it checks |
|---|---|
| Contains (ci) / Not Contains (ci) | A case-insensitive whole-string or substring match, or its inverse. |
| Equals (ci) / Not Equals (ci) | A case-insensitive whole-string match, or its inverse. |
| Equals / Not Equals | A case-sensitive whole-string match, or its inverse. |
| Exists / Not Exists | Whether the selected column has a non-empty value, or does not. |
| In / Not In | Whether the value is, or is not, in a comma-separated list. |
| Regex | A regular-expression pattern; flags are supported, for example /[ab]/i. |
| Matches / Not Matches | A regular-expression-like pattern without flags, or its inverse, for example [ab]. |
| Starts-With (ci) / Not Starts-With (ci) | A case-insensitive match at the beginning of the value, or its inverse. |
| Starts-With (cs) / Not Starts-With (cs) | A case-sensitive match at the beginning of the value, or its inverse. |
Expression items cannot evaluate a column from another table directly. Use a lookup when you need to test whether a value exists in a different system table.
ParametersDirect link to Parameters
Parameters replace a fixed expression value. They do not add new filter behavior; they make the filter reusable when a caller supplies a different value.
Common uses include:
- Reusing a filter in multiple roles with similar inclusion criteria.
- Supplying the member-filter value in a role generator.
- Reusing a lookup filter in an app or workflow with a runtime value.
An input parameter has a data type and default value. A variable parameter takes its value from a NIM variable. The default is only used while previewing the filter during configuration; a caller overrides it when it uses the parameterized filter.
Add a parameter to an expressionDirect link to Add a parameter to an expression
- Edit the filter containing the expression item.
- On the item, select Constant/Parameter. The fixed-value field becomes Value Of Parameter.
- Open Parameters and select Add Parameter. Name it, then choose
inputfor a caller-supplied value orvariablefor a value from a NIM variable. Aninputparameter also needs a data type and preview default. - Return to the expression and choose the new parameter from Value Of Parameter.
- Preview records with representative values and select Save.
To use a fixed value again, select Parameter/Constant, enter the constant, and save the filter.