Codes that can be added by a system administrator are called "user-defined." The user selects a code word and enters any other necessary code information to create a new code. Because codes created at a specific location are inherited by locations that are farther down in the organizational structure, it is important to use code words and descriptions that will be easily identified by other locations.

"System-defined" codes are codes that have been created as part of the Odyssey system. These codes cannot be changed by users. There are some user-defined codes that must be associated with system-defined codes. For example, financial categories can be set up and maintained by the user. However, each of the financial categories must be associated with one of the base financial categories, which are system defined.