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6 videos are tagged with arel

01/10/2015, 10:00 AM
Vlcsnap 2015 02 04 10h00m18s201 thumb

ActiveRecord can't do it? Arel can! Active Record is awesome. But how does ActiveRecord handle generating complex SQL queries? Under the hood it's handled by Arel. Most of the time, Rails developers don't have to know about how Arel works. But sometimes Active Record can't satisfy our needs. Also Arel has many strengths not exposed through Active Record. Let's experiment with Arel directly and wield great SQL power in database agnostic way. Oh and did I mention, this is a fun talk, even for us, to “perform”.

04/22/2014, 09:20 PM
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Rating: Everyone
Viewed 4,783 times
Date Posted:

We all love Rails, and lots of us love ActiveRecord. It's intuitive and easy to use in small apps that don't have lots of models. You can select, join, and where your way into a great, working app in no time. Then your app starts to grow, you add more models, and you need to start building more and more complex queries. This talk describes how to harness the awesomeness of aRel, ActiveRecord's powerful relational algebra system, to perform arbitrarily complex queries using nothing but pure Ruby.

Cameron Dutro works on Twitter's International Engineering team, primarily on the Twitter Translation Center, a large Rails application. He's been building stuff in Ruby for the past three years, including the TwitterCLDR internationalization library, and loving every minute of it.

06/26/2014, 09:00 PM
Vipul amler thumb

Active Record is awesome. But how does ActiveRecord handle generating complex SQL queries? Under the hood it's handled by Arel. Most of the time, Rails developers don't have to know about how Arel works.

But sometimes Active Record can't satisfy our needs. Also Arel has many strengths not exposed through Active Record.

Let's experiment with Arel directly and wield great SQL power in database agnostic way.

08/22/2014, 04:00 PM
Building an orm with arel  walking up the astree w  prathamesh sonpatki   vipul a m at madison  ruby   youtube thumb

We all love ActiveRecord. Its Awesome. But how does ActiveRecord
handle generating complex SQL queries? How Joins, Associations and Table Relations are handled?

Most of its power comes from ARel. ARel is packed up with many features for complex query generation.
Lets build our own ORM on top of ARel to see it in action.
In the process we will also explore about how ActiveRecord hooks up with ARel.

This talk describes Relational Algebra, Object and Collection modeling of ARel using a tiny ORM at its base. At the end of talk you will be equipped with better understanding of ARel and AR as an ORM.

09/18/2010, 11:45 PM
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Rating: Everyone
Viewed 1,302 times
Date Posted: 04/17/2011

Arel (also known as ActiveRelation) is the Ruby relational algebra engine powering ActiveRecord in Rails 3. By replacing string concatenation with an object model to express SQL queries, Arel had a big immediate impact on the ActiveRecord codebase and opens the door for more powerful Object Relation Mapping (ORM) functionality in the future. This talk will introduce the concept of relational algebra, cover the past, present and future of Arel, and dive into how you can leverage it today either on its own, or in your Rails 3 applications.

04/23/2012, 11:30 PM
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Rating: Everyone
Viewed 1,729 times
Date Posted: 06/19/2012

Scopes are a great way of encapsulating query logic in a granular, reusable way. This talk will cover some techniques you can use to keep those scopes as composable and portable as possible. We’ll cover how to use Arel directly, while avoiding the common practice of using SQL fragments, and show you how this can make your scopes more reusable, while at the same time preventing you from using database vendor specific operators, such as ILIKE.