Table of Contents

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  1. Preface
  2. Working with Transformations
  3. Aggregator Transformation
  4. Custom Transformation
  5. Custom Transformation Functions
  6. Data Masking Transformation
  7. Data Masking Examples
  8. Expression Transformation
  9. External Procedure Transformation
  10. Filter Transformation
  11. HTTP Transformation
  12. Identity Resolution Transformation
  13. Java Transformation
  14. Java Transformation API Reference
  15. Java Expressions
  16. Java Transformation Example
  17. Joiner Transformation
  18. Lookup Transformation
  19. Lookup Caches
  20. Dynamic Lookup Cache
  21. Normalizer Transformation
  22. Rank Transformation
  23. Router Transformation
  24. Sequence Generator Transformation
  25. Sorter Transformation
  26. Source Qualifier Transformation
  27. SQL Transformation
  28. Using the SQL Transformation in a Mapping
  29. Stored Procedure Transformation
  30. Transaction Control Transformation
  31. Union Transformation
  32. Unstructured Data Transformation
  33. Update Strategy Transformation
  34. XML Transformations

Transformation Guide

Transformation Guide

Defining Expression Strings in Parameter Files

Defining Expression Strings in Parameter Files

The Integration Service expands the mapping parameters and variables in an expression after it parses the expression. If you have an expression that changes frequently, you can define the expression string in a parameter file so that you do not have to update the mappings that use the expression when the expression changes.
To define an expression string in a parameter file, you create a mapping parameter or variable to store the expression string, and set the parameter or variable to the expression string in the parameter file. The parameter or variable you create must have IsExprVar set to true. When IsExprVar is true, the Integration Service expands the parameter or variable before it parses the expression.
For example, to define the expression
IIF(color=‘red’,5)
in a parameter file, perform the following steps:
  1. In the mapping that uses the expression, create a mapping parameter $$Exp. Set IsExprVar to true and set the datatype to String.
  2. In the Expression Editor, set the expression to the name of the mapping parameter as follows:
    $$Exp
  3. Configure the session or workflow to use a parameter file.
  4. In the parameter file, set the value of $$Exp to the expression string as follows:
    $$Exp=IIF(color=‘red’,5)

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