Do you know “in theory” the difference between “includes”, “preload”, “eager_load” and “joins”, but you still think that you need more examples to really understand how to use them?
Here you will find a set of examples to help you understand how you can use this 4 methods.
You can find the code on bhserna/preloading_examples
This is the code that I used for the post: Examples to learn the difference between preload, includes or eager_load.
On lib/examples.rb you will find a list of examples with:
You can use this code to play a little more and try different things.
Create a postgres database with createdb preloading_examples. As
you can see the in db/config.rb the name of the database is hardcoded, so
you will need to create a database with that name.
Install the dependencies with bundle install.
Run the seeds with ruby db/seeds.rb. You can also update the data that
you want to use, there.
Run the examples with ruby lib/examples.rb.
Learn just enough fundamentals to be fluent preloading associations with ActiveRecord, and start helping your team to avoid n+1 queries on production.