A mapping/design can utilize parameters and variables to store information during the execution of the logic. Each parameter and variable is defined with a specific data type and their main purpose is to provide increased development flexibility for various complex business requirements.
Parameters are different from variables in the fact that:
- The value of a parameter is fixed during the run of the mapping Variables can change in value during run-time
- Both parameters and variables can be accessed from any component in the mapping which supports it.
In Informatica, Parameters/variables can be declared and assigned values at different stages of the mapping design like the parameter file, mapping level etc..
Now the Question is, What is the order in which Informatica looks for these parameter values while execution.
The Order of Execution of Parameter Values in Informatica:
1. Parameter File
2. Value Assigned in Pre-Session Variable Assignment
3. Value saved in the Repository
4. Initial Value defined for the variable at declaration level
5. The default value defined by Informatica for the Datatype of the defined variable
Informatica Checks for the variable values in the above order and stops and assigns the value to the parameter/variable when it finds a value. In case there are values defined in two parameter files and the Parameter files are assigned at both Session Level and Workflow level, then the Parameter file defined at the Workflow level always overrides the Parameter file defined at the Session Level.