外键约束求助

[DarrenFu1019]

我在《深入浅出MYSQL数据库开发、优化与管理维护》一书中照着抄了一段代码，可是提示出错，怎么找也没找到错误原因，还请各位高手不吝赐教！

书本上抄的代码是：create table city(city_id smallint unsigned not null auto_increment,city varchar(50) not null,country_id smallint unsigned not null,last_update timestamp not null default current_timestamp on update current_timestamp,primary key(city_id),key idx_fk_country_id(country_id),constraint 'fk_city_country' foreign key(country_id) references country(country_id) on delete restrict on update cascade)engine=innodb default charset=utf8;

错误提示：error 1064(42000):you have an error in your sql syntax;check the manual that corresponds to your mysql server version for the right syntax to use near ''fk_city_country' foreign key(country_id) references country(country_id) on dele' at line 1

请各位高手帮我看看错误出在哪儿，谢谢了！

[iihero_]

这个应该是印刷错误，或者写书的人把``括起符弄成''括起符了。，就是把`fk_city_country`弄成'fk_city_country'了。
你copy下边的文本就OK了：
create table city(city_id smallint unsigned not null
auto_increment,city varchar(50) not null,country_id smallint
unsigned not null,last_update timestamp not null default
current_timestamp on update current_timestamp,
primary key(city_id),constraint `fk_city_country` foreign key(country_id)
references country(country_id) on delete restrict on update cascade) engine=innodb
default charset=utf8;
或者不用指定constraint name，使用：
create table city(city_id smallint unsigned not null
auto_increment,city varchar(50) not null,country_id smallint
unsigned not null,last_update timestamp not null default
current_timestamp on update current_timestamp,
primary key(city_id),foreign key(country_id)
references country(country_id) on delete restrict on update cascade) engine=innodb
default charset=utf8;

如：
mysql> create table city(city_id smallint unsigned not null
-> auto_increment,city varchar(50) not null,country_id smallint
-> unsigned not null,last_update timestamp not null default
-> current_timestamp on update current_timestamp,
-> primary key(city_id),foreign key(country_id)
-> references country(country_id) on delete restrict on update cascade) engine=innodb
-> default charset=utf8;
Query OK, 0 rows affected (0.02 sec)

[DarrenFu1019]

好了，非常感谢！

[wwwwb]

'fk_city_country'-> `fk_city_country`