Hi Mani,
One should never be loading the data into Presentation schema. Only the data load schema should be used to load the data.
You switch from the data load schema to the presentation schema to make newly loaded data available for use in reports.An automatic operation then copies the data from the presentation schema to the data load schema so that it is ready for the next data load.You can also manually start the copy operation
Also note that:
Data from Ariba Contract Management, Ariba Sourcing, Ariba Supplier Information Management, and Ariba Supplier Information and Performance Management is pulled automatically into the presentation schema
for more details - Refer to reporting-dataload-admin.pdf or raise a ticket with Ariba support team using connect.ariba.com.
Regards
Vilas