Expression transformation

Expression transformation is a passive and connected transformation.

The Expression transformation is used to calculate values to perform any non-aggregate calculations in a single row before we write to the target. We can also use the Expression transformation to test conditional statements before we output the results to target tables or other transformations.

There are 3 types of ports in Expression Transformation:

1. Input
2. Output
3. Variable: Used to store any temporary calculation.

Calculating Values

To use the Expression transformation to calculate values for a single row, we must include the following ports:

• Input or input/output ports for each value used in the calculation: For example: To calculate Total Salary, we need salary and commission.
• Output port for the expression: We enter one expression for each output port. The return value for the output port needs to match the return value of the expression.

We can enter multiple expressions in a single Expression transformation. We can create any number of output ports in the transformation.