What is incremental loading in Informatica?

Question

I am performing SCD type 1 mapping. I have these source tables.

1.CUSTOMERS, (Source customer File)
2.PRODUCTS (Source Product File)
3.SALES   (source Sales file)

Also, these are dimensions and fact tables.

1.D_CUSTOMERS (SCD 1),
2.D_PRODUCTS (SCD 1) and
3.F_SALES_DLY (Fact)

Sales contains daily level data. Fact table will have sales & quantity data aggregated for product & for a month.(Fact table should be incremental for 24 months.(It should always contain 24 months of data)

I am bit confused, How to make fact table incremental? If i try to use any transformation(filter) to get last 24 months records, is it feasible solution?

Please suggest me something..

Thanks...

Answer 1

Incremental load is adding/inserting only changed/latest data from the source.In incremental loading,history data could remain as it is along with the new data or overwritten by incremental data.

When use Incremental loading:

Let suppose you a mapping for load the data from employee table to a employee_target table on the hire date basis. Again let suppose you already move the employee data from source to target up to the employees hire date 31-12-2009.Your organization now want to load data on employee_target today. Your target already have the data of that employees having hire date up to 31-12-2009.so you now pickup the source data which are hiring from 1-1-2010 to till date. That’s why you needn’t take the data before than that date, if you do that wrongly it is overhead for loading data again in target which is already exists. So in source qualifier you filter the records as per hire date and you can also parameterized the hire date that help from which date you want to load data upon target.