Override the Rails create_table migration template

Do not index

URL

In the previous post about using a ULID as a primary key for you ActiveRecord models I described the changes needed for the create_table migrations. I like to not think about that all the time and run into weird errors while migration my database when I forgot to make the id a binary type.

For this we can override the create_table_migration template that Rails uses. Just add a file at this location lib/template/migration/templates/create_table_migration.rb.ttin your Rails application and add the following:

class <%= migration_class_name %> < ActiveRecord::Migration[<%= ActiveRecord::Migration.current_version %>]
  def change
    create_table :<%= table_name %>, id: false do |t|
      t.binary :id, limit: 16, primary_key: true
<% attributes.each do |attribute| -%>
<% if attribute.password_digest? -%>
      t.string :password_digest<%= attribute.inject_options %>
<% elsif attribute.token? -%>
      t.string :<%= attribute.name %><%= attribute.inject_options %>
<% elsif attribute.reference? -%>
      t.<%= attribute.type %> :<%= attribute.name %><%= attribute.inject_options %><%= foreign_key_type %>
<% elsif !attribute.virtual? -%>
      t.<%= attribute.type %> :<%= attribute.name %><%= attribute.inject_options %>
<% end -%>
<% end -%>
<% if options[:timestamps] %>
      t.timestamps
<% end -%>
    end
<% attributes.select(&:token?).each do |attribute| -%>
    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>, unique: true
<% end -%>
<% attributes_with_index.each do |attribute| -%>
    add_index :<%= table_name %>, :<%= attribute.index_name %><%= attribute.inject_index_options %>
<% end -%>
  end
end

This adds the id:false to the create_table method and will add the binary id by default. The original file from Rails can be found here:

rails/create_table_migration.rb.tt at main · rails/rails

Ruby on Rails. Contribute to rails/rails development by creating an account on GitHub.

https://github.com/rails/rails/blob/main/activerecord/lib/rails/generators/active_record/migration/templates/create_table_migration.rb.tt

UPDATE

This has been changed by this PR

Model Generator Source Paths Should Allow for Customization by spencerneste · Pull Request #47181 · rails/rails

Motivation / Background This Pull Request has been created because #13972 was closed. It has the same content as the mentioned PR, with the addition of a test that would fail without the new code, ...

https://github.com/rails/rails/pull/47181/files

We now can place the migration template override in a better place, next to the activemodel template here: lib/templates/active_record/model/create_table_migration.rb.tt

Override the Rails create_table migration template

Related posts

How to use ULID primary keys in Rails