Evaluating Expressions - Informatica

When the Debugger pauses, use the Expression Editor to evaluate expressions using mapping variables and ports in a selected transformation.

You can evaluate expressions in the following transformations:

• Aggregator transformation
• Expression transformation
• Filter transformation
• Rank transformation
• Router transformation
• Update Strategy transformation

When you create an expression, you use references to ports within the transformation. The Expression Editor does not display ports for other transformations in the mapping. When you evaluate the expression, the Debugger returns the result of the expression in a message box.

Evaluating Expressions Using Mapping Variables

If you define variables in the mapping, you can evaluate the start value or current value of the mapping variable. To find the start value of a mapping variable, evaluate the mapping variable only.

The Debugger uses the following process to determine the start value of a mapping variable:

1. Parameter file. If you use a parameter file, the Debugger returns the value in the parameter file.
2. Repository. If you do not use a parameter file, the Debugger returns the value in the repository.
3. Initial value. If the repository does not have a stored value for the variable, the Debugger returns the initial value configured in the mapping variable.
4. Default value. If you do not configure an initial value for the mapping variable, the Debugger returns the default value based on datatypes.

To find the current value of a mapping variable, evaluate the mapping variable with one of the variable functions, such as SetMaxVariable or SetCountVariable. The Designer displays only the mapping variables associated with the transformations in the mapping. To view mapping variables associated with a mapplet, select the transformation within the expanded mapplet when the Debugger is running.

Steps to Evaluate Expressions

To evaluate an expression while the Debugger pauses, complete the following steps:

To evaluate an expression while the Debugger pauses:

1. Select the transformation for which you want to evaluate an expression.
2. Click Mappings > Debugger > Evaluate Expression.
3. Enter an expression in the Expression Editor that references ports in the selected transformation.
4. To validate the expression, click Validate.
5. To evaluate the expression, click Evaluate.

If the expression is valid, the Integration Service evaluates it. The Integration Service returns the result of the expression in a message box.