扶手：序列化值作为逗号分隔的，而不是YAML [英] Rails: Serialize value as comma-seperated and not as YAML

问题描述

我正在寻找一种方式来存储，例如一个序列化值。标识中的一列。在之前声称这是不是最佳设计：列用于相关记录的ID，但显示的记录时，将只使用 - 与选择的列，因此没有查询制成，没有联接将在此列作无论是。

I'm looking for a way to store a serialized value of eg. IDs in a column. In before claims that this is not an optimal design: the column is used for IDs of associated records, but will only be used when displaying the record - so no queries are made with selection on the column and no joins will be made on this column either.

在我的Rails可以通过序列化列：

In Rails I can serialize the column by using:

class Activity
   serialize :data
end

这EN codeS的列YAML。对于旧酒，因为我只存储一个只包含整数一维数组，我觉得它更适合将其保存为一个逗号分隔值。

This encodes the column as YAML. For legacy sake and since I'm only storing one dimensional arrays containing only integers, I find it more suitable to store it as a comma-seperated value.

我已经成功地实施了基本的访问是这样的：

I've successfully implemented basic accessors like this:

def data=(ids)
    ids = ids.join(",") if ids.is_a?(Array)
    write_attribute(:data, ids)
end

def data
    (read_attribute(:data) || "").split(",")
end

本作品pretty的罚款。不过，我想补充类似数组的方法将这些属性：

This works pretty fine. However I'd like to add array-like methods to this attribute:

activity = Activity.first
activity.data << 42
...

我将如何做到这一点？

How would I do this?

谢谢！

推荐答案

您可以使用的 composed_of 功能的解释在这个岗位。 它应该是这样的：

You can do it with composed_of feature as explained in this post. It should be something like:

  composed_of :data, :class_name => 'Array', :mapping => %w(data to_csv),
                   :constructor => Proc.new {|column| column.to_csv},
                   :converter   => Proc.new {|column| column.to_csv}

  after_validation do |u|
    u.data = u.data if u.data.dirty? # Force to serialize
  end

还没有，虽然进行了测试。

Haven't tested it though.

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