续集中的复杂约束

Question

我在Sequel migratin中有以下约束：

constraint(:date_is_1_feb_or_1_aug, 'EXTRACT(MONTH FROM date)::INT IN (2,8) AND EXTRACT(DAY FROM date)::INT = 1')

有没有办法简化这个并使用DSL？

Answer 1

constraint(:date_is_1_feb_or_1_aug,
   Sequel.extract(:month, :date).cast(Integer)=>[2,8],
   Sequel.extract(:day, :date).cast(Integer)=>1)