The DDL meaning of an enum declaration is exactly the same as a C language enum: i.e it specifies an enumerated type. Its syntax is also the same:
enum [declarator] {enum-list} ;where declarator is the name used to refer to the enumerated type elsewhere in the schema. For example:
enum FLOWCONTROL { XON, CTS }; class example_using_enum { FLOWCONTROL fc; };