In response to the person who asked (in a Comment to this post – and thank you for the question – it is an excellent one!) the difference between a session law and a code, specifically between the Oregon Revised Statutes (ORS) and the Oregon Laws, I offer this. It is about as brief a description as can be made, but it is followed by suggestions for further reading.
(Keep in mind, that this is interesting stuff to law librarians and not necessarily to others, so you can always visit your local law library to see and hear and not just read about these government publications. We love this stuff: a previous Washington D.C. tour highlight for a bunch of us law librarians was a visit to the Office of Law Revision Counsel that prepares the U.S. Code (not to be confused with the session law, the U.S. Statutes at Large).
Oregon Laws: a chronological compilation of laws passed by the Legislature and signed by the Governor. Published officially by Oregon in a set called, Oregon Laws.