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

Conditional Dynamic Cache Updates

Conditional Dynamic Cache Updates

You can update dynamic lookup cache based on the results of a boolean expression. The Integration Service updates the cache when the expression is true.
For example, you might have a product number, quantity on hand, and a timestamp column in a target table. You need to update the quantity on hand with the latest source values. You can update the quantity on hand when the source data has a timestamp greater than the timestamp in the dynamic cache. Create an expression in the Lookup transformation similar to the following expression:
lookup_timestamp < input_timestamp
The expression can include the lookup and the input ports. You can access built-in, mapping, and parameter variables. You can include user-defined functions and refer to unconnected transformations.
The expression returns true, false, or NULL. If the result of the expression is NULL, the expression is false. The Integration Service does not update the cache. You can add a check for NULL values in the expression if you need to change the expression result to true. The default expression value is true.
Create the expression with the Transformation Developer. You cannot override the
Dynamic Cache Update Condition
at the session level.

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