CSV 到 DataMapper 导入

Question

这可能很简单，但我对 ruby​​ 和活动记录还很陌生。

我有一个数据库的 CSV 转储，我正在尝试使用 DataMapper 将其导入数据库。我无法理解我应该在模型中定义哪种类型的关系，以便它与定义的 CSV 匹配。

这是我从 CSV 获得的数据：

Stages:
id
staff_id
project_id
job_id
company_id

Projects:
id
company_id

Jobs:
id
project_id
company_id

Client:
id

Staff:
id

例如：阶段是属于_to项目还是这个has_many关系？

Answer 1

我假设客户 == 公司。这里是 ActiveRecord 的示例

class Stage < ActiveRecord::Base
  belongs_to :staff
  belongs_to :project
  belongs_to :job
  belongs_to :company, :class => "Client"
end

class Project < ActiveRecord::Base
  belongs_to :company, :class => "Client"
  has_many :stages
end

class Job < ActiveRecord::Base
  belongs_to :project
  belongs_to :company, :class => "Client"
  has_many :stages
end

class Client < ActiveRecord::Base
  has_many :jobs, :foreign_key => "company_id"
  has_many :projects, :foreign_key => "company_id"
  has_many :stages, :foreign_key => "company_id"
end

class Staff < ActiveRecord::Base
  has_many :stages
end

这里是 DataMapper 的示例：

class Stage
  include DataMapper::Resource
  property :id, Serial
  belongs_to :staff
  belongs_to :project
  belongs_to :job
  belongs_to :company, "Client"
end

class Project
  include DataMapper::Resource
  property :id, Serial
  belongs_to :company, "Client"
  has n, :stages
end

class Job
  include DataMapper::Resource
  property :id, Serial
  belongs_to :project
  belongs_to :company, "Client"
  has n, :stages
end

class Client
  include DataMapper::Resource
  property :id, Serial
  has n, :jobs, :foreign_key => "company_id"
  has n, :projects, :foreign_key => "company_id"
  has n, :stages, :foreign_key => "company_id"
end

class Staff
  include DataMapper::Resource
  property :id, Serial
  has n, :stages
end

对于导入，您应该按特殊顺序进行：

1. Client、Staff，因为它们可以独立于所有其他模型而存在
2. Project，它只依赖于Client
3. Job，取决于 Project 和 Client
4. Stage，取决于 Staff、Project、Job 和 Client