Active record playground, for rails developers that want an easy way to practice with active record in isolation

I want to share with you my “Active record playground template”.

It is a template that you could use as a guide or by cloning the repo and following the instructions in the README if you want to play with some Active Record models in isolation and without creating a full rails app.

I was repeating my self over and over

I was setting up the structure of this template from scratch over and over again until I decided to do it in a little more general way.

Now it is much more faster and easier for me to start playing with Active Record in isolation. And now, I hope it also can help you.

The default structure of this template will make some decision for you:

1. The starting Gemfile

It includes activerecord and pg, but also the faker gem, because it will be help you to define your examples data.

2. A place for your models

On lib/models.rb you can define the objects/records that you need. This file is already required to run your seeds and examples.

3. A place for your seeds

On db/seed.rb you will be able to define your seeds using the objects defined on lib/models.rb. You will also be able to run them with “ruby db/seed.rb”.

4. A place for the schema

As this is “playing” code, instead of migration, you will create directly the schema on db/schema.rb.

5. The db setup command

With “ruby db/setup.rb” you will create or re-create the database, load the schema and run the seeds.

6. A place to define your examples

You will have an /examples dir, to add the examples files that you need.

Requiring examples/config will require the database initialization code and the models defined on lib/models.rb

You can run the examples with ruby examples/<file name>

ruby example/00_example.rb

Use the template

Use this template if you want to play with Active Record in isolation without creating a full rails app.

You can find the template on https://github.com/bhserna/active_record_playground

You can use it as a guide or by cloning the repo and following the instructions on the README.

Some examples of using this template

Here are some examples that I have shared, using this template (or previous versions of it):

Do you want to solve n+1 queries with confidence?

Understand the methods (joins, includes, etc...) to work with associations.
Identify when active record will execute a query.
And the tools that can help you detect n+1 queries (like the bullet gem).