题解 | #对first_name创建唯一索引uniq_idx_firstname#

Mysql 创建索引的方法：
alter table actor add unique uniq_idx_firstname(first_name);
alter table actor add index idx_lastname(last_name);

sqllite创建索引方法：
create unique index uniq_idx_firstname on actor(first_name);
create index idx_lastname on actor(last_name);