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  1. Preface
  2. Mappings
  3. Mapplets
  4. Mapping Parameters
  5. Where to Assign Parameters
  6. Mapping Outputs
  7. Generate a Mapping from an SQL Query
  8. Dynamic Mappings
  9. How to Develop and Run a Dynamic Mapping
  10. Dynamic Mapping Use Cases
  11. Mapping Administration
  12. Export to PowerCenter
  13. Import From PowerCenter
  14. Performance Tuning
  15. Pushdown Optimization
  16. Partitioned Mappings
  17. Developer Tool Naming Conventions

Developer Mapping Guide

Developer Mapping Guide

Parameterizing the Dynamic Expression

Parameterizing the Dynamic Expression

When you use a dynamic expression in an Aggregator, Expression, or Rank transformation, you can create an expression parameter. The expression parameter contains a complete expression.

Example

You work for a consulting firm in the infrastructure sector that collects data on the forces that weather phenomena exert on different locations in the architecture of a building. You want to use a dynamic mapping to transform the data that you collect and round the value of the force that is exerted.
In the dynamic mapping, you use an Expression transformation that receives the following generated input ports:
Force_Location_A Decimal Force_Location_B Decimal Force_Location_C Decimal
You create a port selector
Port_Selector_Force
that has a selection rule to include ports that have the prefix
Force_
. You also create a dynamic output port
Dynamic_Forces
and use an expression parameter for the dynamic expression. The default value of the expression parameter is the following expression:
CEIL(Port_Selector_Force)
You can also use the expression parameter in multiple parameter sets. For example, the default value of the expression parameter in the one parameter set might be
CEIL(Port_Selector_Force)
. In another parameter set, the default value of the expression parameter might be
FLOOR(Port_Selector_Force)
.

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