不使用任何方法或使用`all（）`生成ActiveRecord :: Relation

Question

Seemingly simple question.

I'm trying to build a ActiveRecord::Relation object from a model without using a method like where() . For example:

@people = Person

@people.where( status: 'active' ) if params(:active)
@people.where( is_smoker: true )  if params(:smokers)

return @people

You can see that if neither active or smokers is set in the params, @people is just the model, not an ActiveRecord::Relation .

I could throw on all at the end of return @people but there must be a better way.

Thoughts?

Answer 1

You can use the .scoped method:

@people = Person.scoped

@people.where( status: 'active' ) if params(:active)
@people.where( is_smoker: true )  if params(:smokers)

return @people

There is also the .unscoped method which basically does the same thing BUT ignores all the default_scopes defined.

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Rails 4: The method .scoped is deprecated , see @FrederickCheung's answer

Answer 2

On rails 3.x, scoped is the way to go. However it is deprecated in Rails 4 and removed in Rails 4.1

For rails 4.0 and higher, all just returns a scope, so you would instead write

@people = Person.all
@people.where( status: 'active' ) if params(:active)
@people.where( is_smoker: true )  if params(:smokers)

return @people