What r the mapping paramaters and maping variables?

Maping parameter represents a constant value that U can define before running a session.A mapping parameter retains the same value throughout the entire session.
When u use the maping parameter ,U declare and use the parameter in a maping or maplet.Then define the value of parameter in a parameter file for the session.
Unlike a mapping parameter,a maping variable represents a value that can change throughout the session.The informatica server saves the value of maping variable to the repository at the end of session run and uses that value next time U run the session.

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Sep 21st, 2004
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Praveen Vasudev

Sep 12th, 2005

Please refer to the documentation for more understanding.
Mapping variables have two identities:
Start value and Current value
Start value = Current value ( when the session starts the execution of the undelying mapping)
Start value <> Current value ( while the session is in progress and the variable value changes in one ore more occasions)
Current value at the end of the session is nothing but the start value for the subsequent run of the same session.

sithusithu
Profile Answers by sithusithu

Jan 19th, 2006

You can use mapping parameters and variables in the SQL query, user-defined join, and source filter of a Source Qualifier transformation. You can also use the system variable $$$SessStartTime.
The Informatica Server first generates an SQL query and scans the query to replace each mapping parameter or variable with its start value. Then it executes the query on the source database.
Cheers,
Sithu

chandrarekha

Sep 12th, 2007

Mapping parameter represents a constant value defined before mapping run.
Mapping reusability can be achieved by using mapping parameters.

Mapping variable represents a value that can be changed during the mapping run.
Mapping variable can be used in incremental loading process.