graphql - Schema from nested JSON list

Question

I have a JSON list which captures one to many relationships.

For example, School can have multiple Class objects and Class can have multiple Student objects, but Student only belongs to one Class and one School:

{
  "School": [ {
    "id": 1,
    "name": "Grad School",
    "Class": [ {
         "name": 101,
         "Student": [ {
              "name": 501,
              "propertyA": "test"
         }]
     }]
  }]
}

I am trying to convert this JSON example into an appropriate schema but the nesting is causing issues. Apollo appears to be able to help but the example below isn't very descriptive: https://launchpad.graphql.com/4nqqqmr19

I'm looking for suggestions on how to handle this situation, whether that be through a JSON schema converter (which handles nested situations) or other.

Answer 1

I think you issue is not really the schema, which to me looks straightforward:

You have these types (everything dummy code as you have not specified in what language/framework you want to provide the GraphQL-Api):

SchoolType
  id ID
  name String
  classes [Class]
  students [Students]

ClassType
  id ID
  name String
  school School
  students [Student]

StudentType
  id ID
  name String
  class Class
  school School

Then we need an entry point

classQueryType
  name "school"
  argument :id, ID
  resolve do
    schools.where(id: argument["id"])

So we have the schema. The bigger work is probably to get the different types to access the JSON Schema in a way that the types above work.

So let's say, we read the JSON data somehow, with the structure you have.

 const DATA = JSON.parse("your-example.json")

We need to convert this into different collections of objects, so we can query them dynamically:

 schools = []
 classes =  []
 people = []

  def build_schools(data)
    data.schools.for_each do |school|
       schools.push(
         name: school.name, 
         id: school.id, 
         classes: build_classes(school)
       )
    end
 end

 def build_classes(school)
   ids = []
   school.classes.for_each do  |class|
     ids.push(class.id)
     classes.push(
       id: class.id
       name: class.name
       school_id: school.id # you create your own references, to associate these objects
       students: build_students(class)
     )
   end
   return ids
 end

 ...

But then you still need to hook this up, with your type system. Which means to write your resolvers:

For example on the StudentType

StudentType
 id ID
 name String
 class Class
 school School
   resolve(object) ->
     school_id = students.where(id: object.id).class_id.school_id
     schools.where(id: school_id)