【PostgreSQL实现 insert ignore】

创建规则忽略错误的数据；操作正确的数据。

create 
    rule [规则名称] as on insert to [表名] 
where 
    exists 
        (select 1 from [表名] where [判断条件]) 
    do instead nothing; 

#下面的规则是：插入数据到表system_lock时，id相同的就忽略。
create 
    rule r_insert_ignore as on insert to system_lock
where 
    exists 
        (select 1 from system_lock where id = new.id) 
    do instead nothing; 

后续就可以用正常的语句insert；