将数据插入 Rails
我是 Rails 新手，无法弄清楚如何将数据插入数据库。
我正在读取 CSV 并希望将这些值加载到数据库中。我的模型看起来像这样。
class Book < ActiveRecord::Base
belongs_to :subject
end
class Subject < ActiveRecord::Base
has_many :books
end
...我的数据是这样的：
Science, Book A
Science, Book B
History, Book C
Math, Book D
我用分隔符分割 CSV 行。
如何以这样的方式插入数据：如果主题存在，子图书记录将添加到现有主题，但如果主题不存在，也会创建新主题？
这是解决此问题的最佳方法还是有人可以推荐更好的方法。
I'm new to rails and had trouble figuring out how to insert data into the db.
I'm reading a CSV and would like to load those values into the db. My model looks something like this.
class Book < ActiveRecord::Base
belongs_to :subject
end
class Subject < ActiveRecord::Base
has_many :books
end
...and my data is something like this:
Science, Book A
Science, Book B
History, Book C
Math, Book D
I'm splitting the CSV rows by the delimiter.
How can insert the data in a way that if a subject exists, the child book record will be added to the existing subject but in the event that a subject doesn't exist, a new subject will be created too?
Is this the best way to go about this or could someone recommend a better approach.
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评论（2）
无需重新发明轮子。将标题行添加到 csv 文件中，将其另存为 subject.csv，然后使用内置的固定装置库加载数据： http://api.rubyonrails.org/classes/Fixtures.html
No need to reinvent the wheel. Add a header row to your csv file, save it as subjects.csv and then use the built in fixtures library to load the data: http://api.rubyonrails.org/classes/Fixtures.html
感谢@idlefingers：
Thanks to @idlefingers for this: