A reusable transformation in Informatica PowerCenter is a pre-built transformation object that can be used multiple times within different mappings. This concept promotes efficiency, consistency, and maintainability in ETL development.
Here's a breakdown:
Core Concept :
- Instead of creating the same transformation logic repeatedly in different mappings, you can create a single, reusable transformation and then reference it as many times as needed.
- This transformation is stored in the Informatica repository, making it accessible to all mappings within the repository.
Benefits of Reusable Transformations :
- Reduced Development Time:
- You only need to create the transformation logic once, saving time and effort.
- Improved Consistency:
- Reusable transformations ensure that the same transformation logic is applied consistently across all mappings.
- Enhanced Maintainability:
- If you need to change the transformation logic, you only need to modify the reusable transformation once, and the changes will be reflected in all mappings that use it.
- Simplified Mapping Design:
- Reusable transformations can simplify complex mapping designs by encapsulating frequently used logic.
- Promotes Standardization:
- Reusable transformations help in standardizing the ETL processes.
How it Works :
- Creation:
- You create a transformation (e.g., Expression, Lookup, Filter) and save it as a reusable transformation in the repository.
- Usage:
- You can then drag and drop the reusable transformation into any mapping.
- When you place a reusable transformation into a mapping, it is displayed with a special icon, to denote that it is a reusable object.
- Modification:
- If you modify the reusable transformation, the changes are automatically propagated to all mappings that use it.
Example :
- Imagine you have a complex expression that performs data cleansing and standardization. You could create this expression as a reusable transformation and then use it in multiple mappings that require data cleansing.
- Another example would be a lookup transformation that looks up country codes, and returns country names. This lookup would be used in many mappings, so making it reusable is very efficient.
