create table city
(
city_code   varchar2(6)  not null,   
city_name	varchar2(60) not null unique,
short_name  varchar2(3)  primary key,
part_type   varchar2(30) ,
country_code  varchar2(4)  references country(country_code) on delete cascade,
gmt_time	varchar2(10) not null,
city_addr1  varchar2(60) ,
city_addr2	varchar2(60) ,
city_addr3	varchar2(60) ,
air_addr1   varchar2(60) ,
air_addr2	varchar2(60) ,
air_addr3	varchar2(60)
)
/