Delta Calculation and Updating multiple tables

Question

We pull data from a System of Records table that contains the most up to date information. The information changes daily so we have a delta process to identify what new records were added, which records were deleted (records that are not found in the table as compared to yesterday) and which were updated. Delta process compares the already loaded data with the newly updated SOR data to find the differences.
Once the delta is established, either new records get added or existing records get updated or existing records are marked as inactive (Deletes). Additions and Updates generally happen across multiple destination tables.
Updates are identified by looking at different columns to see if any one column is changed. These columns end up in different tables.
Example
Source Delta Table, S1
ID COL1 COL2 COL3 ACTION
1 abc xyz pqr A
2 bcd lmn def U
S1.Col1 maps to Destination Table D1.Col23
S1.Col2 maps to Destination Table D2.Col45
S1.Col3 maps to Destination Table D3.Col11
Currently all tables are updated irrespective of whether the relevant data has changed or not (All 3 destination tables are updated).
I would like to know which of the Columns for a given row has changed values so that I can update only the relevant tables.
Thus if additional columns are available that act as flags
Source Delta Table, S1
ID COL1 COL2 COL3 ACTION COL1 COL2 COL3
1 abc xyz pqr A - - -
2 bcd lmn def U N Y N
3 kjh qwe iop U Y Y N
then for incoming ID=2, I just have to update Destination Table D2 and not D1 and D3
for incoming ID= 3, I have to update Destination Tables D1 and D2 but not D3.
How can I achieve that?
This is mainly to improve performance as the processing time is very short - Faster the delta processing, better will it be.
Thanks in advance.

Answer 1

Thanks for your response.
My question was more towards establishing what has changed.
Given a table, which is updated daily, how does one efficiently establish which data has changed?
Here is an example to clarify my question further
The Source table has the following data on a particular day
Data in Source table on Monday               
ID     Col1     Col2     Col3
1     abc     bcd     cde
2     def     efg     fgh
3     ghi     hij     ijk
4     jkl     klm     lmn
Copy of the above data is stored in a Old Data table
Data in Source table on Tuesday               
ID     Col1     Col2     Col3
1     bac     bcd     cde
2     def     gfe     fgh
3     ghi     jih     jik
5     mno     nop     opq
Data in Source Table is compared with data in Old Data Table
Delta established by comparing Source Table with Old Data Table                    
ID     Col1     Col2     Col3     Delta_Flag
1     bac     bcd     cde     U
2     def     gfe     fgh     U
4                    D
5     mno     nop     opq     A
Rows with IDs 1 & 2 were updated - thus to be updated
Row with ID 3 - no change so not seen in delta
Row with ID 4 was not found - thus to be deleted
Row with ID 5 was new - To be added
I can do the above easily. I would like to a step further to be able to say for updates
Row with ID 1 has Col1 changed
Row with ID 2 has Col2 and Col3 changed
Is there an easy way to do this?