Source based CDC based on date fields i am planning to extract data

I am planning to extract data based on create date and update date.

if it is based on created dat, then i append/insert records to target table, if it is based on updated_date, then will do an update to teh exiting row in target table.

I am confused at one point, how can i update, can i use map_operation transform object to insert or update rows in the target table.

If i use map_op, do i need to use table _comparison transform object?

Since i already have my extracted data for new rows and updated rows, why do i need a table comparison that is where i am confused.

Please kindly provide me a logic how to handle scenario.

Thanks a lot for the helpful info.

Roger