Why does a single record lookup return an array? (Rails beginner)

Question

I have a where operation on a model that returns a single object. But I can't seem to use it in object notation (it appears to return an array with the object at [0]).

store = Store.where("some_id = ?", some_id)

puts store.name  # doesn't work

puts store  # shows array with the object at [0]

Answer 1

Because sometimes you don't know how many objects a query should return, so for consistency you always get an array.

To get a single object use

store = Store.where("some_id = ?", some_id).first

If you are looking for the primary ID of the model, you can also use

store = Store.find(some_id)

which will raise a RecrodNotFound exception (handled by rails as a 404 by default) if it doesn't find the object.

Answer 2

There are also dynamic finders

Store.find_by_some_id(some_id)

They are equivalent to

Store.where(:some_id => some_id).first

Answer 3

Where clause in rails 3.x will always return and arel objec, which you can use for method chaining.

Thus return statement of the where clause is always an array.

For accessing the first element you have to do

object.first as suggested by Jakub