I deleted this topic after deciding that my answers were already scattered around the forum in the various polymorphism and inheritance topics. Here I am a week later, still failing to find what I feel is an adequate solution to a relatively simple problem.

In a relational database (or any other table based one for that matter) how would you model the above — where a document/page/record/whatever is composed of many different types of content?

For example, the record that I’d want to pull from the DB would look something like this after whatever joins, etc were done:

%Document{
  name: "Example",
  id: 1,
  content: [
    %Video{
      index: 0,
      url: "something.com/ajsha",
      description: "all about the video",
      author_id: 3,  (%User{})
    },
   %Title{
     index: 1,
     text: "My title"
   },
   %Image{
     index: 2,
     url: "something.com/akshgdakj.jpg",
     caption: "Blah blah",
     uploader_id: 5, (%User{})
     photographer_id: 28, (%User{})
    },
    [...]
  ]
}

Thinking about it, this would have been equally relevant when I was putting together the schema for my CrossFit app recently. A solution to this could help there to.

Others have referred to this problem as a polymorphic has_many as opposed to the polymorphic belongs_to that is often talked about (and has solutions in the Ecto docs). That topic has been my main point of reference, although I’m not wedded to the idea of an Animal => Cat/Dog/Whatever relation as the original poster.

I’ve scratched my head, got my Google-fu on, read some books and even explored other means of storing the data and still can’t really work it out.

Help me!