题解 | #对first_name创建唯一索引uniq_i

# 两种方法
/*第一种
create unique index uniq_idx_firstname
on actor(first_name);
create index idx_lastname
on actor(last_name);
*/
# 第二种
alter table actor add unique index uniq_idx_firstname(first_name);
alter table actor add index idx_lastname(last_name);