Basically, mapping parameters and mapping variables represent values in mappings and mapplets.
- Mapping parameters represent constant values that are defined before running a session.
- After creation, parameters appear in Expression Editor.
- These parameters can be used in source qualifier filter, in user-defined joins, or for overriding.
- As opposed to mapping parameters, mapping variables can change values during sessions.
- The last value of a mapping variable is saved to the repository at the end of each successful session by the Integration Service. However, it is possible to override saved values with parameter files.
- Basically, mapping variables are used to perform incremental reads of data sources.