将数据库中的值设置为False取决于其他值，否则为True / False

Question

I am trying to set a value of an attribute in my MySQL DB using a ternary operator that is dependent on another variable/value that is available in the same model.

item.rb has a belongs_to relationship to auction.rb . An instance of an auction can be online_only or not. I am trying to set an attribute on an item instance called manual_close that is dependent on wether or not the auction is online_only or not.

so I have the following:

Item.rb:

def as_json(**options)
  json = {
    "manual_close" => self.manual_close?
  }
end

def manual_close?
  !online_only? false : self.manual_close
end

def online_only?
  auction && auction.online_only?
end

Say that item.online_only? == false item.online_only? == false then item.manual_close should == false if item.online_only? == true item.online_only? == true then item.manual_close can either be true or false.

Some rails c output:

a = Auction, i = Item. The json part is right but when I do item.manual_close it should be false instead of true.

Any help would be much appreciated.

Answer 1

I think the problem here is that you are not updating your model in your database.

Defining a method called manual_close? will only override the method manual_close? (with the question mark) and will not affect the manual_close attribute in your database.

You will have to explicitly update manual_close in your database to get the results you are looking for.

i.update(manual_close: i.manual_close?)

I would recommend calling this line from an after_save callback on your Auction model. That way, every time the the auction model is updated, the item model will correctly reflect the state it needs to be.