Question

我正在向数据库中的现有表添加一列。迁移在此处创建：

// ♥ rails g migration AddFieldToRecipes
Running via Spring preloader in process 80952
  invoke  active_record
  create    db/migrate/20180628220935_add_field_to_recipes.rb

在此处编辑：

class AddFieldToRecipes < ActiveRecord::Migration[5.2]
  def change
   add_column :recipes, :cooked, :boolean, null: false, default: false
  end
end

在这里运行：

// ♥ rails db:migrate
== 20180628220935 AddFieldToRecipes: migrating 
================================
-- add_column(:recipes, :cooked, :boolean, {:null=>false, 
:default=>false})
-> 0.0079s
== 20180628220935 AddFieldToRecipes: migrated (0.0080s) 
=======================

是否更改架构：

  create_table "recipes", force: :cascade do |t|
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.boolean "cooked", default: false, null: false
  end

运行时ActiveRecord会看到更改： ActiveRecord::Base.connection.columns("recipes")

=> [#<ActiveRecord::ConnectionAdapters::PostgreSQLColumn:0x00007f8b69f91018
  @collation=nil,
  @comment=nil,
  @default=nil,
  @default_function="nextval('recipes_id_seq'::regclass)",
  @max_identifier_length=63,
  @name="id",
  @null=false,
  @sql_type_metadata=
   #<ActiveRecord::ConnectionAdapters::SqlTypeMetadata:0x00007f8b69f912c0 @limit=8, @precision=nil, @scale=nil, @sql_type="bigint", @type=:integer>,
  @table_name="recipes">,
 #<ActiveRecord::ConnectionAdapters::PostgreSQLColumn:0x00007f8b69f905c8
  @collation=nil,
  @comment=nil,
  @default=nil,
  @default_function=nil,
  @max_identifier_length=63,
  @name="created_at",
  @null=false,
  @sql_type_metadata=
   #<ActiveRecord::ConnectionAdapters::SqlTypeMetadata:0x00007f8b69f90960
    @limit=nil,
    @precision=nil,
    @scale=nil,
    @sql_type="timestamp without time zone",
    @type=:datetime>,
  @table_name="recipes">,
 #<ActiveRecord::ConnectionAdapters::PostgreSQLColumn:0x00007f8b6ad6f860
  @collation=nil,
  @comment=nil,
  @default=nil,
  @default_function=nil,
  @max_identifier_length=63,
  @name="updated_at",
  @null=false,
  @sql_type_metadata=
   #<ActiveRecord::ConnectionAdapters::SqlTypeMetadata:0x00007f8b6ad6fc48
    @limit=nil,
    @precision=nil,
    @scale=nil,
    @sql_type="timestamp without time zone",
    @type=:datetime>,
  @table_name="recipes">,
 #<ActiveRecord::ConnectionAdapters::PostgreSQLColumn:0x00007f8b6ad6edc0
  @collation=nil,
  @comment=nil,
  @default="false",
  @default_function=nil,
  @max_identifier_length=63,
  @name="cooked",
  @null=false,
  @sql_type_metadata=
   #<ActiveRecord::ConnectionAdapters::SqlTypeMetadata:0x00007f8b6ad6ef78 @limit=nil, @precision=nil, @scale=nil, @sql_type="boolean", @type=:boolean>,
  @table_name="recipes">]

但在控制台（或在应用程序中）时不会反映在模型上：

[1] pry(main)> Recipe.columns.map { |c| c.name }
=> ["id", "title", "description", "author", "user_id", "type", "created_at", "updated_at"]

所以我尝试重置列信息：

[2] pry(main)> Recipe.reset_column_information
=> {true=>#<Concurrent::Map:0x007f8b69681cc0 entries=0 default_proc=nil>, false=>#<Concurrent::Map:0x007f8b69681c20 entries=0 default_proc=nil>}

仍然没有变化：

[3] pry(main)> Recipe.columns.map { |c| c.name }
=> ["id", "title", "description", "author", "user_id", "type", "created_at", "updated_at"]

基于此处找到的许多（许多）问题/答案（也是the same exact question with no answer的另一个问题），我回滚了迁移并重新运行了它-同样。回滚，然后重新加载架构，重新运行-相同。由于是开发人员，因此我也删除了数据库，创建，迁移了相同的数据库。

我想念的是什么？我只想让recipe.cooked向我显示是非。

Rails迁移将列添加到架构，但不添加到PostgreSQL数据库

0 个答案: