The read-only attribute tells the system whether to allow the database user to make additions and modifications to the class. Each relation has four attributes. The arity attribute tells the system how many arguments the relation takes. In Infoserver, this is almost always 2. The style attribute tells the system how to present the attribute on query pages.
Possible choices are menu , number , string , typein , and noquery .
Menus and numbers are self-evident. The option attribute relates a relation and a possible value for that relation. On query pages, options are presented in the order they are entered into the system. The documentation attribute gives a documentation string to be used when the database user clicks on that relation name. If no documentation string is supplied, Infoserver does not allow the user to click on the relation name.