Code of Hammurabi

Among the oldest known legal codes, the Code of Hammurabi is quite detailed. You can see a translation here. Discussion can be found here. Other notes.
As you can see from the text, it is intensively concentrated on legal formulations. Like most legal systems, it does not derive from an enumerated set of principles, but rather is a series of prescriptions, transgressions, and penalties for transgressions.

Hippocratic Oath

Probably the first significant professional ethical code, it is still in use today; there is a modern revision that has become popular in the United States.
A translation and some discussion of the classical version can be found here.
A modern version with much discussion can be found here.
A collection of various medical codes is available here