How to store a Reference Object I want to clone from? Use Singleton?

Question

Situation:

• There is a Project Resource that has many Resources A each of them having many Resources B
• When a new Project is created it shall already start with clones of Resources A having clones of Resources B
• There shall be a Reference Project whose Resources A and B (through A) are cloned from
• Cloning is done because in this way new Projects can update their resources A and B without changing the Reference Project and vice versa

Question:

• How to implement this in Rails?

Ideas:

• Implement a singleton class ''ReferenceProject < Project'' which inherits from Project
  • But STI would be overdone for just one Object?
• Introduce a new column "is_reference_project" to Project
  • But how to ensure that there is only one?

Thanks for any input! duddle

Answer 1

I am now doing it this way:

• Adding a column to Project called "is_reference" (:boolean)
• Validating on model level that there is only one at the same time according to:
  • Stackoverflow: only one instance of a model in rails
• Adding named_scopes for the Project model
• Adding a ReferenceProjects Controller operating on named_scope