- A mapplet is a reusable object that we create in the Mapplet Designer.
- It contains a set of transformations and lets us reuse that transformation logic in multiple mappings.
- Created in Mapplet Designer in Designer Tool.
Mapplets help simplify mappings in the following ways:
- Include source definitions: Use multiple source definitions and source qualifiers to provide source data for a mapping.
- Accept data from sources in a mapping
- Include multiple transformations: As many transformations as we need.
- Pass data to multiple transformations: We can create a mapplet to feed data to multiple transformations. Each Output transformation in a mapplet represents one output group in a mapplet.
- Contain unused ports: We do not have to connect all mapplet input and output ports in a mapping.
Mapplet input can originate from a source definition and/or from an Input transformation in the mapplet. We can create multiple pipelines in a mapplet.
- We use Mapplet Input transformation to give input to mapplet.
- Use of Mapplet Input transformation is optional.
The output of a mapplet is not connected to any target table.
- We must use Mapplet Output transformation to store mapplet output.
- A mapplet must contain at least one Output transformation with at least one connected port in the mapplet.
· EMP and DEPT will be source tables.
· Output will be given to transformation Mapplet_Out.
Steps:
- Open folder where we want to create the mapping.
- Click Tools -> Mapplet Designer.
- Click Mapplets-> Create-> Give name. Ex: mplt_example1
- Drag EMP and DEPT table.
- Use Joiner transformation as described earlier to join them.
- Transformation -> Create -> Select Expression for list -> Create -> Done
- Pass all ports from joiner to expression and then calculate total salary as described in expression transformation.
- Now Transformation -> Create -> Select Mapplet Out from list –> Create -> Give name and then done.
- Pass all ports from expression to Mapplet output.
- Mapplet -> Validate
- Repository -> Save
- We can mapplet in mapping by just dragging the mapplet from mapplet folder on left pane as we drag source and target tables.
- When we use the mapplet in a mapping, the mapplet object displays only the ports from the Input and Output transformations. These are referred to as the mapplet input and mapplet output ports.
- Make sure to give correct connection information in session.
transformation to filter records whose Total Salary is >= 1500.
· mplt_example1 will be source.
· Create target table same as Mapplet_out transformation as in picture above. Creating Mapping
- Open folder where we want to create the mapping.
- Click Tools -> Mapping Designer.
- Click Mapping-> Create-> Give name. Ex: m_mplt_example1
- Drag mplt_Example1 and target table.
- Transformation -> Create -> Select Filter for list -> Create -> Done.
- Drag all ports from mplt_example1 to filter and give filter condition.
- Connect all ports from filter to target. We can add more transformations after filter if needed.
- Validate mapping and Save it.
- Make session and workflow.
- Give connection information for mapplet source tables.
- Give connection information for target table.
- Run workflow and see result.
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