In Informatica PowerCenter, mapping parameters and mapping variables are used to make mappings more flexible and reusable. While they both hold values, they differ in how those values are handled. Here's a breakdown:
Mapping Parameters :
- Definition:
- A mapping parameter represents a constant value that you can define before a session runs.
- The value of a mapping parameter remains unchanged throughout the entire session execution.
- Purpose:
- To provide values that may change between sessions, but remain constant within a single session.
- Examples:
- Database connection details (schema names, etc.)
- File paths
- Static filter values
- Key Characteristics:
- Values are typically defined in a parameter file.
- They provide a way to configure a mapping without modifying the mapping itself.
- They are useful for environment-specific configurations (development, testing, production).
Mapping Variables :
- Definition:
- A mapping variable represents a value that can change during a session's execution.
- The Integration Service can save the latest value of a mapping variable to the repository at the end of a successful session.
- Purpose:
- To store and update values that change as a session progresses.
- To track information between sessions.
- Examples:
- Incremental load tracking (last successful load date/time)
- Counters
- Maximum/minimum values processed
- Key Characteristics:
- Values can be updated using variable functions within a mapping (e.g.,
SetMaxVariable, SetCountVariable).
- The Integration Service can persist variable values between sessions.
- They are useful for tracking state and managing incremental data processing.
In summary :
- Parameters are for constant values that might change between session executions.
- Variables are for dynamic values that can change during session execution, and are able to hold those changing values between sessions.
