Expression Transformation 

Expression transformation to calculate values in a single row.Use the Expression transformation to perform non-aggregate calculations.

For example, you might need to adjust employee salaries, concatenate first and last names, or convert strings to numbers.

(Read also: Informatica_interview Q&A)

Transformation type:
Passive
Connected 

Ports:
Input,output,variable.

Mapping:

Expression Transformation Components

You can create an Expression transformation in the Transformation Developer or the Mapping Designer.

An Expression transformation contains the following tabs:

	Transformation. Enter the name and description of the transformation. The naming convention for an Expression transformation is EXP_TransformationName. You can also make the transformation reusable.
	Ports. Create and configure ports.
	Properties. Configure the tracing level to determine the amount of transaction detail reported in the session log file.
	Metadata Extensions. Specify the extension name, datatype, precision, and value. You can also create reusable metadata extensions. calculate values  for a single row using the Expression transformation, you must include the following ports: Input or input/output ports. Provides values used in a calculation. For example, if you need to calculate the total price for an order, create two input or input/output ports. One port provides the unit price and the other provides the quantity ordered. Output ports. Provides the return value of the expression. You enter the expression as a configuration option for the output port. You can also configure a default value for each port.