How to convert ActiveRecord results into an array of hashes

Question

I have an ActiveRecord result of a find operation:

tasks_records = TaskStoreStatus.find(
  :all,
  :select => "task_id, store_name, store_region",
  :conditions => ["task_status = ? and store_id = ?", "f", store_id]
)

Now I want to convert this results into an array of hashes like this:

[0] ->  { :task_d => 10, :store_name=> "Koramanagala", :store_region=> "India" }

[1] -> { :task_d => 10, :store_name=> "Koramanagala", :store_region=> "India" }

[2] ->  { :task_d => 10, :store_name=> "Koramanagala", :store_region=> "India" }

so that I will be able to iterate through the array and to add more elements to hashes and later to convert the result into JSON for my API response. How can I do this?

Solution 1

as_json

You should use as_json method which converts ActiveRecord objects to Ruby Hashes despite its name

tasks_records = TaskStoreStatus.all
tasks_records = tasks_records.as_json

# You can now add new records and return the result as json by calling `to_json`

tasks_records << TaskStoreStatus.last.as_json
tasks_records << { :task_id => 10, :store_name => "Koramanagala", :store_region => "India" }
tasks_records.to_json

serializable_hash

You can also convert any ActiveRecord objects to a Hash with serializable_hash and you can convert any ActiveRecord results to an Array with to_a, so for your example :

tasks_records = TaskStoreStatus.all
tasks_records.to_a.map(&:serializable_hash)

And if you want an ugly solution for Rails prior to v2.3

JSON.parse(tasks_records.to_json) # please don't do it

Solution 2

May be?

result.map(&:attributes)

If you need symbols keys:

result.map { |r| r.attributes.symbolize_keys }

Solution 3

For current ActiveRecord (4.2.4+) there is a method to_hash on the Result object that returns an array of hashes. You can then map over it and convert to symbolized hashes:

# Get an array of hashes representing the result (column => value):
result.to_hash
# => [{"id" => 1, "title" => "title_1", "body" => "body_1"},
      {"id" => 2, "title" => "title_2", "body" => "body_2"},
      ...
     ]

result.to_hash.map(&:symbolize_keys)
# => [{:id => 1, :title => "title_1", :body => "body_1"},
      {:id => 2, :title => "title_2", :body => "body_2"},
      ...
     ]

See the ActiveRecord::Result docs for more info.

Solution 4

try this one :-

data = Model_name.last

data.attributes

View more solutions

Comments

[Léo]

+1 For suggesting serializable_hash - this is the first time I've ever come across an answer that mentions this. Sadly I am currently using the last JSON solution, but will now look at using serializable_hash. I just need to find out how to include the class name with each record, same as you might get if you include root in JSON.

[hdorio]

@Dom웃 If I understand correctly see this: stackoverflow.com/questions/17090891/…

[Fredrik E]

@Dom see my answer below.

[W.M.]

Cannot be simpler and clearer than this. Thank you very much.

[Rigo]

Another possible way is tasks_records = TaskStoreStatus.all.map(&:attributes).

[Phil]

A note if your version of ActiveRecord is not recognising to_hash method: try to_ary instead. Strangely this worked for me.

[alexventuraio]

Really great solutions over here, but my question could be What are the benefits of using either .as_json, &:serializable_hash and &:attributes ? Does it has to do with ActiveRecord helpers or directly with performance? thanks in advance guys! @Dom @Rigo @Fredrik E