Rails-BulkChangeTable.md

Pattern: Missing use of change_table with bulk: true

Issue: -

Description

This rule checks whether alter queries are combinable. If combinable queries are detected, it suggests to you to use change_table with bulk: true instead. When use this method, make combinable alter queries a bulk alter query.

The bulk option is only supported on the MySQL and the PostgreSQL (5.2 later) adapter; thus it will automatically detect an adapter from development environment in config/database.yml when the Database option is not set. If the adapter is not mysql2 or postgresql, this rule ignores offenses.

Examples

# bad
def change
  add_column :users, :name, :string, null: false
  add_column :users, :nickname, :string

  # ALTER TABLE `users` ADD `name` varchar(255) NOT NULL
  # ALTER TABLE `users` ADD `nickname` varchar(255)
end

# good
def change
  change_table :users, bulk: true do |t|
    t.string :name, null: false
    t.string :nickname
  end

  # ALTER TABLE `users` ADD `name` varchar(255) NOT NULL,
  #                     ADD `nickname` varchar(255)
end

# bad
def change
  change_table :users do |t|
    t.string :name, null: false
    t.string :nickname
  end
end

# good
def change
  change_table :users, bulk: true do |t|
    t.string :name, null: false
    t.string :nickname
  end
end

# good
# When you don't want to combine alter queries.
def change
  change_table :users, bulk: false do |t|
    t.string :name, null: false
    t.string :nickname
  end
end

Default configuration

Attribute	Value
Database	<none>
Include	db/migrate/*.rb

Further Reading

• RuboCop - Rails/BulkChangeTable