Fact Table is an entity which represents the numerical measurements of any business. It means we create the fact tables for loading the numerical data. For Example, in a banking model the account numbers and balances are the measurements with in the fact tables. In a star schema there will be facts and dimension tables to load in any data warehouse environments. You will generally load the Dimension tables first and then Facts.Facts will have the relative information of dimension.
InfoSphere DataStage job can use
Slowly Changing Dimension stage to perform updating and loading of dimension and fact tables. After completion, you will be able to configure the SCD stage for history-tracking changes and in-place changes, and use the output of the stage to update an associated fact table. Step by step details in link above under Slowly Changing Dimension Stage.
-Ritesh