Rails和JSON数据，只有在更新或新的情况下才会覆盖

Question

我有一个从外部URL获取JSON数据并保存到我的数据库的cronjob。我正在寻找一个选项，只添加或更新自上次rake任务以来新的或已更改的记录。目前它只是创建旧数据。

佣金任务

           Intent intent; //Initialize it later as per your switch  case condition.
            switch (position) {
                case 1: //Initialize as per your condition
                    intent = new Intent(MainActivity.this, MainActivity2.class);
                    break;
            }
if(intent!=null) //Check here if its not null. Else it will crash your app.
            startActivity(intent);

Answer 1

为实现这一点，我做了：

json['Property'].each do |data|
 property = Property.find_or_create_by(id: data['id'])
 property.id = data['id']
 property.street = data['street']
 property.town = data['town']
 property.postcode = data['postcode']
 property.save
end

感谢@Sajin。