Proper management of Multirelational types

[jstoes]

I’m currently trying to create a proper relationship between Product, Category, and Subcategory types, but I’m struggling to keep it working as intended. My goal is to create a system where I can use an index to get all the Product refs by Category or by Subcategory. Currently I imagine that each Product document would then have a list of category names and a list of subcategory names which is connected to the actual Category and Subcategory documents (Categories and Subcategories would also keep a list of Product names, all for readability). Based on my understanding though, relations would lock this solution to Ref connections within a different helper Collection/Index, which is also alright, just harder to read what a product is connected to.

Now onto the current confusion with my implementation…
I read through the documentation on relations in FQL but I’m not sure I really understand it fully yet. Here is my graphql schema:

type Product {
  productName: String! @unique
  categories: [Category!] @relation(name: "product_category")
  subcategories: [Subcategory!] @relation(name: "product_subcategory")}

type Category {
  categoryName: String! @unique  <-- I'd add a relation here if it was possible
  subcategories: [Subcategory!] @relation
  products: [Product!] @relation(name: "product_category")
}

type Subcategory {
  subcategoryName: String! @unique <-- I'd add a relation here if it was possible
  category: Category! <-- Subcategory *might* be able to have multiple Categories
  products: [Product!] @relation(name: "product_subcategory")
}

Using this schema, I created a Category and linked a Subcategory to it using the create mutation (So now I have a separate helper collection called category_subcategory which manages this).

When I tried to make use of this new Category by connecting it to the product:

mutation {
  partialUpdateProduct(id: "myProductId", data: {
    categories: [
       {connect: "myCategoryId"}
    ]
  }) {
    _id
    categories {
      categoryName
      subcategories {
        data
        {subcategoryName}
      }
    }
  }
}

I run into this error:

Expected type ‘ID!’, found ‘{connect: "myCategoryId"}’. String or Int value expected

I honestly just want the Product’s category and subcategory to be connected to the category and subcategory for easier viewing, but all I really need to store is just the name. I feel like if I could get the products to have a list of category names and subcategory names, but have it be connected to existing categories/subcategories it would in turn be cleaner. I guess whatever works with the best scalability would be the route I’d want to take. I appreciate any comments or suggestions. Thanks!

[ptpaterson]

@jstoes

{connect: "myCategoryId"}

As you noted, references are used to manage relationships, which are more efficient for fetching the related documents than additional indexes on an extra field such as categoryName.

Replace myCategoryId with a document reference ID and your query should work.

In order to use your name field, you would need to create a customer resolver. You could use this to establish connections for easier to read mutations, but materializing the results would still rely on the underlying reference ids.

type Mutation {
  connectCategoryToProduct(productName: String!, categoryName: String!): Product @resolver
}

mutation {
  connectCategoryToProduct(productName: "Thing1", categoryName: "Gizmos") {
    _id
    categories {
      categoryName
      subcategories {
        data
        {subcategoryName}
      }
    }
  }
}

[jstoes]

Thanks this is helpful, I think I’m going to alter it a bit to just have Category and Product where Category has multiple levels and keeps track of each child Category, that way I can add subcategories with time and have it query for Products by each Category. I’ll have to make some functions to help manage d3coupling/removing these categories. Hopefully it goes well