Designer Guide

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Understanding the Transformations

The following table describes the function of each transformation in the Type 2 Dimension/Flag Current mapping:

Transformation Name	Transformation Type	Description
SQ_ SourceName	Source Qualifier or Application Source Qualifier	Selects all rows from the source you choose in the Mapping Wizard.
LKP_GetData	Lookup	Caches the existing target table. Compares key columns in the source against corresponding key columns in the target. When matching keys exist, LKP_GetData returns additional column data from the target for comparison. Passes all rows to EXP_DetectChanges.
EXP_DetectChanges	Expression	Uses the following expression to flag source rows that do not have matching keys in the target. The expression returns TRUE if a matching key does not exist in the target, indicating the row is new: IIF(ISNULL(PM_PRIMARYKEY),TRUE,FALSE) Populates the NewFlag port with the results. Uses the following expression to flag source rows that have a matching key in the target and contain changes in the specified columns. The expression returns TRUE only if a matching key exists in the target, which indicates the row is not new, and if it detects a difference between source and target columns: IIF(ISNULL(PM_PRIMARYKEY) AND (SourceColumnName<>PM_PREV_TargetColumnName) AND (other comparisons) TRUE,FALSE) Populates the ChangedFlag port with the results. Passes all rows to FIL_InsertNewRecord, FIL_InsertChangedRecord, and FIL_UpdateChangedRecord.