ActiveRecord raw result method.

[Evgeniy Sokovikov]

Hello. Is it possible to get raw sql query result from ActiveRecord::Relation ?

Now I can make it this way:

sql = Note.select('count(*), commit_id').group(:commit_id).to_sql

ActiveRecord::Base.connection.execute(sql).to_a

I would like something like this:

Note.select('count(*), commit_id').group(:commit_id).raw

But didn't find such method.

[Dheeraj Kumar]

+1, I do this a lot.

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[Rafael Mendonça França]

+1, too.

I was planning to add this method because calling `to_sql` is not a good solution. I think the name we choose was `select_all`.

Rafael Mendonça França
http://twitter.com/rafaelfranca
https://github.com/rafaelfranca

[Yves Senn]

+1 from me as well. This would be a great addition to the current API.

Cheers,

— Yves Senn

[Xavier Noria]

Should that mimick the low-level API? select_value, select_rows, etc?

On the other hand I feel Arel and #to_sql are out of hand. In the beginning this was considered to be private to AR (this was certainly the point of view of Pratik, who implemented the initial integration IIRC). AR could change completely Arel with something else in theory as long as the public interface was respected.

But Arel and #to_sql seem to be used widely :(.

[Dheeraj Kumar]

How about #to_a and #to_h instead?

#to_h would return the results as a hash, useful when you are retrieving a single row, but many columns.

#to_a would return the results as an array of hashes, useful when you have multiple rows.

[Rafael Mendonça França]

to_a is already used to return an Array of objects.

select_rows seems good to me.

But Arel and #to_sql seem to be used widely.

Yes, this is sad. They was never public API. But I think we can’t do anything besides make clear what is public and what is private API.

Rafael Mendonça França
http://twitter.com/rafaelfranca
https://github.com/rafaelfranca

[Yves Senn]

We should keep #to_sql and Arel as private API. The use-case to get the raw response from the driver remains.

It would be nice to use ActiveRecord to build the SQL but get access to the raw driver result and not the mapped objects.

Do the lower level methods like `select_all`, `select_values`, etc. accept Relations?

The current documentation is a bit confusing about the API (see http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/DatabaseStatements.html#method-i-select_values):

  * The method is in the docs, so it’s assumed to be public.

  * We name the argument arel, which let’s you in belief that arel is public as well

  * The example uses raw SQL.

It would be good to get some light into the dark.

[Dheeraj Kumar]

#to_sql + #execute is widely used, because it's a legitimate, and popular use case. Sometimes, we just need pure ruby objects. AR models become an overhead in those situations.

[Rafael Mendonça França]

I was discussing with Aaron and we believe that passing relations to these methods should not be advised. This is why we want to add a method to relation to get the low level values.

Rafael Mendonça França
http://twitter.com/rafaelfranca
https://github.com/rafaelfranca

[Dheeraj Kumar]

so... `select_one` and `select_all`, maybe?

[Xavier Noria]

On Thu, Apr 10, 2014 at 7:06 PM, Dheeraj Kumar <a.dheer...@gmail.com> wrote:

#to_sql + #execute is widely used, because it's a legitimate, and popular use case. Sometimes, we just need pure ruby objects. AR models become an overhead in those situations.

AR::Base#connection and its API are totally public, but #to_sql wasn't intended to be. AR is not a SQL builder, it is a layer between Ruby and databases.

That's why guides have never covered Arel etc., those are tools used by AR to build SQL *internally*, not to be exposed to end-users.

I'd bet #to_sql ended up in api.rubyonrails.org because nobody nodoc'ed it, I doubt it was intentional.

[lingceng]

I know it's been a long time from the last reply.

But I really want some method return raw results in ActiveRecord.

Actually I use ActiveRecord as a sql builder for some complex query. And it's useful in most cases.

I added a patch for my project to do the following query:

    PayRecord.group(:settlement_id, :pm).having('count(*) > 1').select("count(*), id, settlement_id, pm").select_all

Here's the patch

  

    class ActiveRecord::Relation

      def select_all

        @klass.connection.select_all(self.to_sql)

      end

    end

@Rafael Mendonça França What's the schedule of this feature?

[Artemiy Solopov]

I'd like a way to work with raw data as it was returned by a SQL query. Mostly because Rails' eager loading has a penchant for not working with ActiveRecord::QueryMethods.select, losing useful data in the process.

As for Arel and #to_sql... Why wasn't it made public? Consider that ActiveRecord doesn't even have a convenient interface for writing greater than/less than queries. Arel could be an answer to this problem, and more.

понедельник, 14 марта 2016 г., 21:45:51 UTC+3 пользователь lingceng написал:

[Daniel Schepers]

* bump * I think this would be a useful feature to have

[Marco Costa]

I took a stab at it: https://github.com/rails/rails/pull/33839

Going through the review process soon.