15. History Preserving Transform:
•The History Preserving transform allows to produce a new row in the target rather than updating an existing row. We can indicate in which columns the transform identifies changes to be preserved.
Data Inputs:
A data set that is the result of a comparison between two images of the same data in which changed data from the newer image are flagged as UPDATE rows and new data from the newer image are flagged as INSERT rows.
Data Output:
A data set that is the result of a comparison between two images of the same data in which changed data from the newer image are flagged as UPDATE rows and new data from the newer image are flagged as INSERT rows.
16. Data Transfer:
•When there is a need of pushing operations to the database server rather than loading Job server, we can use Data_Transfer as a Transformation step in Data services.
•The idea is to push down resource-consuming operations to database server such as Joins, Group By and Sorts using a temporary staging Area.
•It writes the data from a source or the output from another transform into a transfer object and subsequently reads data from the transfer object. The transfer type can be a relational database table, persistent cache table, or file.
•During run time, a file(unstructured.txt) is created temporarily, and vanish after execution.