Table of Contents

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  1. Preface
  2. Transformations
  3. Source transformation
  4. Target transformation
  5. Aggregator transformation
  6. Cleanse transformation
  7. Data Masking transformation
  8. Deduplicate transformation
  9. Expression transformation
  10. Filter transformation
  11. Hierarchy Builder transformation
  12. Hierarchy Parser transformation
  13. Hierarchy Processor transformation
  14. Input transformation
  15. Java transformation
  16. Java transformation API reference
  17. Joiner transformation
  18. Labeler transformation
  19. Lookup transformation
  20. Mapplet transformation
  21. Normalizer transformation
  22. Output transformation
  23. Parse transformation
  24. Python transformation
  25. Rank transformation
  26. Router transformation
  27. Rule Specification transformation
  28. Sequence Generator transformation
  29. Sorter transformation
  30. SQL transformation
  31. Structure Parser transformation
  32. Transaction Control transformation
  33. Union transformation
  34. Velocity transformation
  35. Verifier transformation
  36. Web Services transformation

Transformations

Transformations

Lookup SQL overrides

Lookup SQL overrides

When a mapping includes a Lookup transformation, the
mapping
task queries the lookup object based on the fields and properties that you configure in the Lookup transformation. The
mapping
task runs a default lookup query when the first row of data enters the Lookup transformation. If the Lookup transformation performs a relational lookup, you can override the default query.
The default query contains a SELECT statement that includes all lookup fields in the mapping. The SELECT statement also contains an ORDER BY clause that orders all columns in the same order in which they appear in the Lookup transformation. To view the default query, run the
mapping
task. The default query appears in the log file.
If you want to change the ORDER BY clause, add a WHERE clause, or transform the lookup data before it is cached, you can override the default query. For example, you might use database functions to adjust the data types or formats in the lookup table to match the data types and formats of fields that are used in the mapping. Or, you might override the default query to query multiple tables.
Override the default query on the
Advanced
tab of the Lookup transformation. Enter the entire SELECT statement in the
Lookup SQL Override
field. Use an alias for each column in the query. If you want to change the ORDER BY clause, you must also append "
--
" to the end of the query to suppress the ORDER BY clause that the
mapping
task generates.

Example

A Lookup transformation returns the following fields from Microsoft SQL Server table ALC_ORDER_DETAILS:
The Return Fields tab of the Lookup transformation lists the following return fields from table ALC_ORDER_DETAILS: ORDERID, PRODUCTID, UNITPRICE, QUANTITY, and DISCOUNT.
The transformation uses the following lookup condition:
ORDERID=in_ORDERID
When you run the mapping task, the following query appears in the log file:
LKPDP_1> DBG_21097 [2018-11-07 14:11:33.509] Lookup Transformation [lkp_ALC_ORDER_DETAILS]: Default sql to create lookup cache: SELECT PRODUCTID,UNITPRICE,QUANTITY,DISCOUNT,ORDERID FROM "icsauto"."ALC_ORDER_DETAILS" ORDER BY ORDERID,PRODUCTID,UNITPRICE,QUANTITY,DISCOUNT
To override the ORDER BY clause and sort by PRODUCTID, enter the following query in the
Lookup SQL Override
field on the
Advanced
tab:
SELECT PRODUCTID AS PRODUCTID, UNITPRICE AS UNITPRICE, QUANTITY AS QUANTITY, DISCOUNT AS DISCOUNT, ORDERID AS ORDERID FROM "icsauto"."ALC_ORDER_DETAILS" ORDER BY PRODUCTID --
When you run the mapping task again, the following query appears in the log file:
LKPDP_1> DBG_21312 [2018-11-07 14:14:36.734] Lookup Transformation [lkp_ALC_ORDER_DETAILS]: Lookup override sql to create cache: SELECT PRODUCTID AS PRODUCTID, UNITPRICE AS UNITPRICE, QUANTITY AS QUANTITY, DISCOUNT AS DISCOUNT, ORDERID AS ORDERID FROM "icsauto"."ALC_ORDER_DETAILS" ORDER BY PRODUCTID -- ORDER BY ORDERID,PRODUCTID,UNITPRICE,QUANTITY,DISCOUNT