Class definition to be undefined should already exist. This command can be executed for any class definition regardless of current context. Only user defined classes can be undefined. User must have CREATE_EXTENSIONMODEL system privilege and has to be connected in single user mode to run this command.
parseUndefineClassCommand = OMBUNDEFINE CLASS_DEFINITION "QUOTED_STRING" [ ( ON | OF ) "modelClause" ] [ CASCADE ] modelClause = ( MODEL "QUOTED_STRING" | PLATFORM "QUOTED_STRING" | CONFIGURATION_TEMPLATE "QUOTED_STRING" ( ON | OF ) PLATFORM "QUOTED_STRING" )