CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-5
Surya
Surya

Reputation: 2719

How to avoid where query on associated models from getting fired twice(Rails)?

Schema: User
id
name string(255)

Schema: Post
id
user_id
title string(255)

In controller I am querying User which has has_many relation with Post This is what I do in the controller

@users = User.posts.where('title = ?','April Contest').group(:id)

Now in view file I am iterating through @users. For every user I need to fetch posts that satisfy title='April Contest'. For me to make this happen, it looks like I have to query again.

This is what I do in view:

@users.each do |user|
  A LOT OF  HTML THAT DISPLAYS DATA OF USER
 user.posts.where('title = ?','April Contest').each do |post|
    SOME HTML THAT DISPLAYS DATA OF POST
 end
end

Please help me avoid this user.posts.where('title = ?','April Contest') in the view file

Upvotes: 0

Views: 72

Answers (2)

Rahul
Rahul

Reputation: 159

Try using eager_load 

@users = User.eager_load(:posts).where("posts.title = ?",'April Contest')

Eager_load loads all association in a single query using LEFT OUTER JOIN.

Now you will be able to access posts without an extra query

Upvotes: 1

Nandhini
Nandhini

Reputation: 665

Try this

First get Users including the posts where title = 'April Contest'

@users = User.includes(:posts).where("posts.title = ?",'April Contest').references(:post)

Now in view you can iterate using @users and get the posts from user.posts

@users.each do |user|
  A LOT OF  HTML THAT DISPLAYS DATA OF USER
 user.posts.each do |post|
    SOME HTML THAT DISPLAYS DATA OF POST
 end
end

This avoid running the query again in view. Try this and let me know

Upvotes: 1

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