使用 fields_for 的 Rails 错误消息

在我的分类帐会计轨道应用程序中，我有一个基金模型

class Fund < ActiveRecord::Base
    belongs_to :agency
    has_many :gl_accounts

    accepts_nested_attributes_for :gl_accounts

    attr_accessible :name, :agency_id, :fund, :user_stamp, :active
    attr_accessible :gl_accounts_attributes

和一个 gl_accounts 模型

class GlAccount < ActiveRecord::Base
    belongs_to :agency
    belongs_to :fund
    has_many :class_sessions
    has_many :facilities

    validates :agency_id, :fund_id, :name, :gl_account_number, :active, :user_stamp, :account_type, :presence => true
    validates_uniqueness_of :account_type, :scope => :fund_id, :if => :unique_account_type

    attr_accessible :agency_id, :fund_id, :name, :gl_account_number, :active, :user_stamp, :account_type

    def unique_account_type
        [3,4,6,7,8].include? account_type
    end

创建新基金时，必须同时创建 5 个 gl_accounts，所以我使用fields_for当为基金创建新记录时，在 gl_account 模型中创建 5 条新记录。一切似乎都正常，直到我提交表格并收到一条错误消息“总账户资金不能为空”。

gl_accounts 模型上没有“fund”属性。我认为也许rails正在删除“_id”部分（因为有一个fund_id外键字段），但我认为使用嵌套模型和fields_for自动在fund_id字段（gl_account模型的外键）中添加正确的值。但即使我在表单中添加一个带有fund_id值的隐藏字段，我仍然收到错误消息说“fund”不能为空。

那么，也许 Rails 试图告诉我我还有其他问题？

这是参数：

{"utf8"=>"✓",
 "authenticity_token"=>"MNWLFOnLOE+ZRsUf9mogf2cq/TeQ+mxtrdaVu3bEgpc=",
 "fund"=>{"agency_id"=>"1",
 "user_stamp"=>"6",
 "name"=>"Junk",
 "fund"=>"44",
 "active"=>"1",
 "gl_accounts_attributes"=>{"0"=>{"agency_id"=>"1",
 "user_stamp"=>"6",
 "account_type"=>"6",
 "name"=>"Cash Account",
 "active"=>"1",
 "fund_id"=>"1",
 "gl_account_number"=>"44-498-965-789"},
 "1"=>{"agency_id"=>"1",
 "user_stamp"=>"6",
 "account_type"=>"7",
 "name"=>"Credit Card Account",
 "active"=>"1",
 "fund_id"=>"1",
 "gl_account_number"=>"44-498-965-163"},
 "2"=>{"agency_id"=>"1",
 "user_stamp"=>"6",
 "account_type"=>"3",
 "name"=>"Customer Account Balances",
 "active"=>"1",
 "fund_id"=>"1",
 "gl_account_number"=>"44-498-965-254"},
 "3"=>{"agency_id"=>"1",
 "user_stamp"=>"6",
 "account_type"=>"8",
 "name"=>"Refunds Pending Account",
 "active"=>"1",
 "fund_id"=>"1",
 "gl_account_number"=>"44-498-965-456"},
 "4"=>{"agency_id"=>"1",
 "user_stamp"=>"6",
 "account_type"=>"4",
 "name"=>"Deferred Revenue Account",
 "active"=>"1",
 "fund_id"=>"1",
 "gl_account_number"=>"44-498-965-159"}}},
 "commit"=>"Add New Fund"}

尝试从 GlaAccount 类中的存在真实验证中删除fund_id。

validates :agency_id, :name, :gl_account_number, :active, :user_stamp, :account_type, :presence => true

并且也不要将fund_id添加为隐藏字段，因为，你是对的，“fields_for”会自动处理该问题，但这将在验证后发生。

因此，您不需要验证fund_id 是否存在。

Update

另外，为了确保fund_id永远不为空，您可以在数据库表中放置一个约束。使用以下代码创建迁移。

change_column :gl_accounts, :fund_id, :integer, :null => false

Update 2

为了确保资金存在，您需要检查资金是否存在而不是fund_id。

validates :fund, :presence => true

为此，您需要声明与“inverse_of”的关联，如下所示。

class Fund < ActiveRecord::Base
  has_many :gl_accounts, inverse_of: :fund
  accepts_nested_attributes_for :gl_accounts
end

class GlAccount < ActiveRecord::Base
  belongs_to :fund, inverse_of: :gl_accounts
  validates_presence_of :fund
end

有关更多详细信息，请参阅本指南。http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html#label-Validating+the+presence+of+a+parent+model http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html#label-Validating+the+presence+of+a+parent+model