ruby on rails find_or_initialize
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ruby on rails find_or_initialize
提问by joe nayyar
Is there any better way to achieve this in Ruby on Rails?
有没有更好的方法在 Ruby on Rails 中实现这一点？
I'm searching for 11 fields and all are required also, and if not found initialize it.
我正在搜索 11 个字段，所有字段也是必需的，如果没有找到，则对其进行初始化。
There will be more required fields adding to it.
将有更多必填字段添加到其中。
This query works perfect for me, but it just doesn't look like the best way to do this.
这个查询对我来说很完美，但它看起来并不是最好的方法。
find_or_initialize_by_make_and_country_and_engine_and_power_and_body_and_doors_and_fuel_and_cylinders_and_transmission_and_gears_and_wheels(model,country,engine,power,body, doors, fuel, cylinders, transmission,gears,wheels)
回答by Filipe Giusti
On rails 3.2 I would do
在 Rails 3.2 上我会做
attributes = {}
Model.where(attributes).first_or_initialize
Documentation http://apidock.com/rails/ActiveRecord/Relation/first_or_initialize
文档http://apidock.com/rails/ActiveRecord/Relation/first_or_initialize
回答by moger777
Considering the sheer number of fields you are using, you probably are better off manually finding the record and initializing it if it does not exist:
考虑到您使用的字段数量庞大，如果记录不存在，您最好手动查找并初始化它：
attributes = {
country: country,
engine: engine,
power: power,
body: body
etc ...
}
record = where(attributes).first
record = new(attributes) unless record
回答by Boat Pathompon
You can define method like this in your model
您可以在模型中定义这样的方法
def self.find_or_initialize_by_field(params)
send("find_or_initialize_by_#{params.keys.join("_and_")}", *params.values)
end
and then you can call this method like
然后你可以像这样调用这个方法
YourModel.find_or_initialize_by_field({country: country, engine: engine})
回答by Pritesh Jain
while using find_or_intialize_by
使用时 find_or_intialize_by
find by key fields , dont assign all the feilds at once
按关键字段查找，不要一次分配所有字段
eg I assume the make is the key field in the model
例如，我假设 make 是模型中的关键字段
car = find_or_initialize_by_make(model)
car.update_attributes(country: country,engine: engine,power: power, body: body,doors: doors ,fuel: fuel,cylinders:cylinders,transmission: transmission, gears: gears, wheels: wheels)
http://api.rubyonrails.org/classes/ActiveRecord/Base.html#label-Dynamic+attribute-based+finders
http://api.rubyonrails.org/classes/ActiveRecord/Base.html#label-Dynamic+attribute-based+finders
