There are two usecases here -
1) For some sources like Siebel which supports soft deletes (typically a binary valued column indicating if the row is deleted or not) then we handle deletes by using a table security filter on that field.
2) For sources like E-Business Suite which does not support soft deletes then here is one way to handle it in Incorta -
This way the deleted rows from the base fact will always be filtered off from the dashboards. If required you can also schedule a periodic full load (for example every week) to flush out the deleted records from the base table.
Another option to build on what Amit mentioned is to have a temp table in the source database (in the case of a database) and install a database trigger on the main table you want to track deletes. This trigger will only be for "on delete" which will only fire when you delete a record. You can then sync that table to the Incorta instance and use as Amit mentioned above as a security filter. If you have any questions let us know.