Table of Contents

Search

  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

Connected and Unconnected Lookups

Connected and Unconnected Lookups

You can configure a connected Lookup transformation or an unconnected Lookup transformation. A connected Lookup transformation is a transformation that has input and output ports that you connect to other transformations in a mapping. An unconnected Lookup transformation appears in the mapping, but is not connected to other transformations.
An unconnected Lookup transformation receives input from the result of a :LKP expression in a transformation such as an Expression transformation or Aggregator transformation. The :LKP expression passes arguments to the Lookup transformation and receives a result back from the Lookup transformation. The :LKP expression can pass lookup results to another expression in the Expression or Aggregator transformation to filter results.
The following table lists the differences between connected and unconnected lookups:
Connected Lookup
Unconnected Lookup
Receives input values directly from the pipeline.
Receives input values from the result of a :LKP expression in another transformation.
Use a dynamic or static cache.
Use a static cache.
Cache includes the lookup source columns in the lookup condition and the lookup source columns that are output ports.
Cache includes all lookup and output ports in the lookup condition and the lookup/return port.
Returns multiple columns from the same row or insert into the dynamic lookup cache.
Returns one column from each row to a return port.
If there is no match for the lookup condition, the Integration Service returns the default value for all output ports. If you configure dynamic caching, the Integration Service inserts rows into the cache or leaves it unchanged.
If there is no match for the lookup condition, the Integration Service returns NULL.
If there is a match for the lookup condition, the Integration Service returns the result of the lookup condition for all lookup/output ports. If you configure dynamic caching, the Integration Service either updates the row the in the cache or leaves the row unchanged.
If a match occurs for the lookup condition, the Integration Service returns the result of the lookup condition to the return port.
Passes multiple output values to another transformation. Link lookup/output ports to another transformation.
Returns one output value to another transformation. The Lookup transformation return port passes the value to the port that contains the :LKP expression in the other transformation.
Supports user-defined default values.
Does not support user-defined default values.

0 COMMENTS

We’d like to hear from you!