麻烦的DataMapper连结一对一的模型

问题描述

使用的PostgreSQL 和的DataMapper 来建立一个辛纳屈的应用程序，运行到一些问题， DataMapper的（我是很新的它，使用轨道/ AR ）。对于每个帐户创建的，它可以是一个艺术家，地点或风扇。只有一个，没有结合。

当用户注册，我可以创建帐户实例罚款，但我无法创建帐户的有1 艺术家或地点或风扇实例（为便于交谈，我们将使用艺术家作为属于模型）。

下面是我目前的模式声明：

 类帐户
    包括的DataMapper ::资源    属性：ID，序列
    ...    有1个，：艺术家：所需=＆GT;假
    有1个，：场地：需要=＆GT;假
    有1个，：风扇：要求=＆GT;假
结束级的艺术家
    包括的DataMapper ::资源    ＃没有ID
    ...    belongs_to的：帐户，：关键=＆GT;真正
结束一流的场馆
    包括的DataMapper ::资源    ＃没有ID
    ...    belongs_to的：帐户，：关键=＆GT;真正
结束范类
    包括的DataMapper ::资源    ＃没有ID
    ...    belongs_to的：帐户，：关键=＆GT;真正
结束
 

这就是我正在努力去注册过程：

 帐户= Account.create（
    ...
）account.Artist = Artist.create（：生物=＆gt;中考）
 

这是目前给我的下一个错误：

 未定义的方法`艺术家='＃为LT＆;帐号：0x007ff2af289840＆GT;
 




解决方案

我想你应该指模型中使用小写字母：

  account.artist = Artist.create（：生物=＆gt;中考）
 

这行：

 有1：艺术家：所需=＆GT;假
 

添加的关系，通过它可以从帐户参考艺术家。

更新

正是你的模型，并好像它的工作。有 DataMapper.finalize 的事情，我想你做到了。

Using PostgreSQL and DataMapper to build a Sinatra app, running into some problems with DataMapper (I'm very new to it, used to Rails/AR). For every Account created, it can either be an Artist, Venue, or Fan. Only one, no combining.

When the user signs up, I can create the Account instance fine, but I'm having trouble creating the account's has 1 Artist or Venue or Fan instance (for ease of conversation, we'll use Artist as the belonging model).

Here's my current model declarations:

class Account
    include DataMapper::Resource

    property :id,           Serial
    ...

    has 1, :artist, :required => false
    has 1, :venue, :required => false
    has 1, :fan, :required => false
end

class Artist
    include DataMapper::Resource

    # no ID
    ...

    belongs_to :account, :key => true
end

class Venue
    include DataMapper::Resource

    # no ID
    ...

    belongs_to :account, :key => true
end

class Fan
    include DataMapper::Resource

    # no ID
    ...

    belongs_to :account, :key => true
end

And here's how I'm trying to go about the sign up process:

account = Account.create(
    ...
)

account.Artist = Artist.create(:bio => "test")

This is currently giving me next error:

undefined method `Artist=' for #<Account:0x007ff2af289840>

解决方案

I guess you should use lowercase letter in referring model:

account.artist = Artist.create(:bio => "test")

This line:

has 1, :artist, :required => false

Add a relation, by which you can refer from Account to Artist.

Updated

This answer has exactly your model and seems like it worked. There is DataMapper.finalize thing, i guess you made it.

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