如何在 rails 上更改 ruby 上的模型属性名称

Question

I want to change false variable name to new one, so I created the true and new one but the old and false one stil stay!

How can remove the false one

irb(main):001:0> item = Item.last Item Load (0.3ms) SELECT "items".* FROM "items" ORDER BY "items"."id" DESC LIMIT ? [["LIMIT", 1]] => #<Item id: 6, title: "Make a cake for your darling", description: "She loves furit ", created_at: "2019-02-27 18:04:15", updated_at: "2019-02-27 18:04:15", user_id: 2, complated_at: nil, completed_at: nil> irb(main):002:0>

I made a typo mistake it must be "completed"

我能做什么？

Answer 1

创建迁移并使用 remove_column 方法更改数据库。

https://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-remove_column

Answer 2

rails g migration remove_complated_at_from_items complated_at:datetime

this line generate those codes

class RemoveComplatedAtFromItems < ActiveRecord::Migration[5.2]
  def change
    remove_column :items, :complated_at, :datetime
  end
end

my current schema.rb file

ActiveRecord::Schema.define(version: 2019_02_27_204841) do
  create_table "items", force: :cascade do |t|
    t.string "title"
    t.text "description"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.integer "user_id"
    t.datetime "completed_at"
    t.datetime "complated_at"
  end

now lets run rails db:migrate

$ rails db:migrate

== 20190227204841 RemoveComplatedAtFromItems: migrating =======================
-- remove_column(:items, :complated_at, :datetime)
   -> 0.0038s
== 20190227204841 RemoveComplatedAtFromItems: migrated (0.0039s) ==============

Seems every things is okay! lets check it schema.rb!

ActiveRecord::Schema.define(version: 2019_02_27_204841) do
  create_table "items", force: :cascade do |t|
    t.string "title"
    t.text "description"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.integer "user_id"
    t.datetime "completed_at"
  end

All is good right now. Last to left lets check the one object!

 rails c
irb(main):001:0> item = Item.last
  Item Load (0.3ms)  SELECT  "items".* FROM "items" ORDER BY "items"."id" DESC LIMIT ?  [["LIMIT", 1]]
=> #<Item id: 6, title: "Make a cake for your darling", description: "She loves furit ", created_at: "2019-02-27 18:04:15", updated_at: "2019-02-27 18:04:15", user_id: 2, completed_at: nil>

DONE!

Answer 3

不要删除列。只需重命名即可。

创建一个新的迁移并放置代码：

rename_column :items, :complated_at, :completed_at

如何在 rails 上更改 ruby 上的模型属性名称

How I can change the model attribute name on ruby on rails

ruby

ruby-on-rails

ruby-on-rails-4