Rails: Get next / previous record

Navigation through associations

Use the power of Rails associations to navigate your records. Let's say you have a User with a bunch of Photos. Here's how you can get to the next and previous photos by a user:

class Photo < ApplicationRecord
  belongs_to :user

  # Moving on up to the East Side, to a deluxe photo in the sky!
  def next
    user.photos.where("id > ?", id).order(:id).first
  end

  # Step back, you're dancing kinda close! Back to the previous photo.
  def previous
    user.photos.where("id < ?", id).order(id: :desc).first
  end
end
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This uses the has_many and belongs_to associations for contextual and efficient record navigation.

Navigation with creation timestamps

If records are organized by timestamps instead of IDs, use timestamp field like created_at:

# We're moving forward in time, like a Time Lord! 
def next_by_created_at
  user.photos.where("created_at > ?", created_at).order(:created_at).first
end

# And now we're stepping back in time, Marty McFly style! 
def previous_by_created_at
  user.photos.where("created_at < ?", created_at).order(created_at: :desc).first
end
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Augmenting record navigation

Consider the user experience and application requirements, and you can enhance single record navigation.

Containing edge cases

Always think about the first and last record. Handle gracefully such cases where there's no next or previous record.

Abstracting methods

Keep it clean and classy! Abstract the logic either within the model or a concern, enriching your code base and ease of maintenance.

Result ordering

Remember the power of ordering! It ensures consistent results, especially crucial when dealing with duplicated created_at timestamps.

Reducing database load

Save the memory! Rather than loading all the associated records, optimize database load by using limit and first.

Advanced next/previous navigation

Embrace these additional techniques to tailor your record navigation.

Navigation with conditions

Add more complex conditions, or scopes, where record navigation has to satisfy certain conditions such as ownership, status, or visibility.

Pagination

Integrate pagination tools like kaminari or will_paginate for record series, improving navigation and performance simultaneously.

Personalized navigation

Consider the context. Users should navigate through records relevant to their interaction within the application.