Here are two simple methods:
Use a tOracleRow component. In the query, type "Delete from tablename where 1 = 1". Do this for each table you want to clear.
Use a tOracleOutput component. In the dropdown for "Action on table", select "Clear Table". This will delete all data in the table before inserting the new data.
Although I am referring to tOracle components, the same function is available for other databases. Just use the right component for the database you are working with.
