Correct, if you use SLT, it will use column store objects in HANA by default, despite being row store objects in Oracle.
No changes will be required in order for the code to run (and probably much faster). However, if your code was written for Oracle and you want to use HANA as a secondary database, you may find that your code benefits from further optimization.
This is because often, developers use SELECT * and Loops. This is not the correct approach for HANA - you need to push the query down into the database.
John