Question

我正在尝试围绕旧数据库弯曲rails。每个表都有一个'datasource'列，它是数据来源的3字符代码。因此，为了唯一地识别和关联其他表，您必须有两条信息（例如帐号和数据源）。

我在下面的has_many关系工作正常，除非我尝试包含在查询中。

# Model Association
has_many :transactions,
         :primary_key => :account,
         :foreign_key => :acnt,
         :order => :ddate,
         :conditions => ['datasource = ?', '#{self.datasource}']

# Controller code FAIL when I loop through results in view and call 'account.transactions'
@accounts = Account.includes(:transactions).where(:lname => 'Smith')

# However, this controller code works when I loop through the results in the view and call 'account.transactions'
@accounts = Account.where(:lname => 'Smith')

# View
<% @accounts.each do |a| %>
  <% a.transactions.each do |t| %>
    <%= t.description %>
  <% end %>
<% end %>

错误：

ActionView::Template::Error (undefined method `datasource' for #<Class:0x1025f25c8>):

在Rails 3中实现此目的的正确方法是什么？

Answer 1

打破并定制finder_sql。看起来它有效，到目前为止......

  has_many :transactions,
           :primary_key => :account,
           :foreign_key => :acnt,
           :finder_sql =>
               'SELECT t.* ' +
               'FROM accounts a, transactions t ' +
               'WHERE a.acnt = t.account AND a.datasource = t.datasource ' +
               'ORDER BY t.ddate'

Answer 2

尝试将您的条件置于引号

之内

has_many :transactions,
         :primary_key => :account,
         :foreign_key => :acnt,
         :order => :ddate,
         :conditions => ['datasource = "#{self.datasource}"']

Answer 3

您的条件陈述是错误的。试试这个。

：conditions =＆gt; ['transactions.datasource = accounts.datasource']

Rails has_many与多个键的关联

3 个答案: