A mapping parameter represents a constant value that you can define before running a session. A mapping parameter retains the same value throughout the entire session.

When you use a mapping parameter, you declare and use the parameter in a mapping or mapplet. Then define the value of the parameter in a parameter file. The Integration Service evaluates all references to the parameter to that value.

For example, you want to use the same session to extract transaction records for each of the customers individually. Instead of creating a separate mapping for each customer account, you can create a mapping parameter to represent a single customer account. Then use the parameter in a source filter to extract only data for that customer account. Before running the session, you enter the value of the parameter in the parameter file.

To reuse the same mapping to extract records for other customer accounts, you can enter a new value for the parameter in the parameter file and run the session. Or, you can create a parameter file for each customer account and start the session with a different parameter file each time using

pmcmd

. By using a parameter file, you reduce the overhead of creating multiple mappings and sessions to extract transaction records for different customer accounts.

When you want to use the same value for a mapping parameter each time you run the session, use the same parameter file for each session run. When you want to change the value of a mapping parameter between sessions you can perform one of the following tasks: