Question

我正在尝试使用StoreModel gem通过类来备份我的jsonb数据。尝试定义数组属性时，出现ArgumentError（未知关键字：array）。例如：

class A
   include StoreModel::Model

   attribute :my_array, :integer, array:true, default:Array.new
end

将其键入irb将产生错误。

经进一步检查，它似乎与StoreModel gem无关。

class A
  include ActiveModel::Model
  include ActiveModel::Attributes

   attribute :my_array, :integer, array:true, default:Array.new
end

将产生相同的结果。根据Attributes API，该类不需要由数据库表支持。但是，当我尝试示例时：

class MyModel < ActiveRecord::Base
  attribute :my_string, :string
  attribute :my_int_array, :integer, array: true
  attribute :my_float_range, :float, range: true
end

model = MyModel.new(
  my_string: "string",
  my_int_array: ["1", "2", "3"],
  my_float_range: "[1,3.5]",
)

在IRB中，它尝试执行SQL查询，因此我得到：

ActiveRecord::StatementInvalid (PG::UndefinedTable: ERROR:  relation "my_models" does not exist)
LINE 8:                WHERE a.attrelid = '"my_models"'::regclass
                                          ^
:               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod,
                     c.collname, col_description(a.attrelid, a.attnum) AS comment
                FROM pg_attribute a
                LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum
                LEFT JOIN pg_type t ON a.atttypid = t.oid
                LEFT JOIN pg_collation c ON a.attcollation = c.oid AND a.attcollation <> t.typcollation
               WHERE a.attrelid = '"my_models"'::regclass
                 AND a.attnum > 0 AND NOT a.attisdropped
               ORDER BY a.attnum

Answer 1

宝石的作者在这里:)问题here中正在进行讨论–我稍后将实现对数组的真正支持，但是有一种解决方法：

定义自定义类型（我将其保留在app / types中）

class ArrayOfStringsType < ActiveRecord::Type::Value
  def type
    :array_of_strings
  end
end

class ArrayOfIntegersType < ActiveRecord::Type::Value
  def type
    :array_of_integers
  end

  def cast(values)
    return if values.blank?
    values.map(&:to_i)
  end
end

注册他们（初始化器是这样做的好地方）：

ActiveModel::Type.register(:array_of_strings, ArrayOfStringsType)
ActiveModel::Type.register(:array_of_integers, ArrayOfIntegersType)

在模型中使用它们：

class Configuration
  include StoreModel::Model

  attribute :colors, :array_of_strings, default: -> { [] }
  attribute :prices, :array_of_integers, default: -> { [] }
end

StoreModel gem似乎不支持数组

1 个答案: