SQL Server 2012 :: Need To Implement Incremental Load In Database

We need to implement incremental load in database. A sample scenario is, there is a view (INCOMEVW) which is build on top of a query like

CREATE VIEW INCOMEVW
AS
SELECT CLIENTID,COUNTRYNAME,SUM(OUTPUT.INCOME) AS INCOME
(SELECT EOCLIENT_ID AS CLIENTID,EOCOUNTRYNAME AS COUNTRYNAME,EOINCOME AS INCOME FROM EOCLIENT C INNER JOIN EOCOUNTRY CT ON
C.COUNTRYCODE=CT.COUNTRYCODE

[code]...

This is a sample view. As of now there is a full load happening from the source(select * from INCOMEVW) and loads to target table tbl_Income.We need to pick only the delta and load to the target table using a staging. The challenge is,

1) If we get the delta(Insert,update or deleted rows in the source tables EOCLIENT,EOCOUNTRY,ENCLIENT,ENCOUNTRY, how to load the incremental to

single target table tbl_Income.

2) How to do the Sum operation with group by in incremental load?

3) We are planning to have a daily incremental load and thinking to create the same table structure as source with Date and Flag column to identify

the date and whether that source row is an Insert or Update or Delete with the flag. But not sure how to frame something like this view and load to single target with Sum operations.