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Data Queries in Rails: Exploring find_all_by & find_by

by | Jan 17, 2023 | Active Record | 0 comments

Ruby on Rails is a powerful web application framework that offers developers numerous ways to query and manipulate data. One common task in Rails development is finding records in a database that meet certain criteria. In this blog post, we will explore two methods for querying data in Rails: find_all_by and find_by.

The Problem

Consider the following code snippet from a Task model in a Rails application:

class TaskController < ApplicationController
  def incomplete
    @tasks = Task.find(:all, :conditions => ['complete = ?', false])
  end

  def last_incomplete 
    @task = Task.find(:first, :conditions => ['complete =?', false], :order => 'created_at DESC')
  end
end

The incomplete method queries the database for all incomplete tasks, while the last_incomplete method finds the latest incomplete task.

While these methods work, there is a better way to achieve the same result using the find_all_by and find_by methods.

The Solution

The find_all_by method allows us to find all records that match a particular value for a given attribute. To find all incomplete tasks, we can replace the incomplete method with the following:

@tasks = Task.find_all_by_complete(false)

This code is more concise and easier to read than the previous implementation.

The find_by method, on the other hand, returns the first record that matches a particular value for a given attribute. To find the latest incomplete task, we can replace the last_incomplete method with the following:

@task = Task.find_by_complete(false, :order => 'created_at DESC')

This code finds the first incomplete task ordered by the created_at column in descending order, effectively giving us the latest incomplete task.

Conclusion

The find_all_by and find_by methods are powerful tools in the Ruby on Rails toolkit for querying data efficiently. By using these methods, we can write concise and readable code that performs database queries with ease.

Kirk
Author: Kirk

Greetings, my name is Kirk. I’m the creator of Rails Zone and a passionate Ruby on Rails developer. During my free time, I develop helpful tools and tutorials that aid fellow Ruby on Rails developers in creating applications with improved efficiency and speed.