CODEWITHSUNDEEP
ruby-on-rails
DDDDDD
DDDDDD

Reputation: 61

Best practices to model and table names

I would like to understand the rails conventions around model and table names. For example:

I have the following models:

class Blog < ApplicationRecord
  has_many :posts
end

class Post < ApplicationRecord
  belongs_to :blog
  has_one :metric
end

class Metric < ApplicationRecord
  belongs_to :post
end

This generates the following tables:

blogs
posts
metrics

This can be confusing because metrics doesn't contain a namespace in the name (like post_metrics). Should I instead create a model PostMetric or perhaps change the name of the table with table_name = 'post_metrics'? Is there a clear rule here?

Thank you.

Upvotes: 1

Views: 937

Answers (2)

max
max

Reputation: 101811

PostMetric is not namespaced. Its just a slightly more descriptive name than just Metric.

Namespacing is when you nest your models in a module for disambiguation or code organization: 

# app/models/blogs/metric.rb
module Blogs
  # table name is blogs_metrics
  class Metric < ApplicationRecord
  end
end

# app/models/posts/metric.rb
module Posts
  # table name is posts_metrics
  class Metric < ApplicationRecord
  end
end

Note that the tables are named plural_plural - blogs_metrics. Rails automatically infers that the class is nested when the first "word" is plural.

There are no hard and fast rules when it comes to naming and code organisation. Its up to you as the author to make the most descriptive names possible without being excessively verbose.

Upvotes: 0

weilandia
weilandia

Reputation: 577

If you're sure that Metric should only be related to Post, then PostMetric or Posts::Metric would be good solutions. For Posts::Metric, you can read more about namespacing ActiveRecord models for organization purposes here.

If you think Metric could be used more broadly, you could leave it as is, but make the relationship polymorphic so that you can relate Metric to other models.

Also, it may make better sense to just embed the Metric data in the post itself by using a jsonb column (though this would make getting Blog level metrics more complex):

add_column :posts, :metrics, :jsonb, null: false, default: {}

Lastly, I would avoid leaving it as Metric and changing the table name. This makes it hard to immediately know that Metric is in fact post_metrics.

Upvotes: 2

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