Using @cascade with optional fields

Users GraphQL
1

Hello, I am trying to get desired results with GraphQL, but don’t know how to get it.
Given following schema:

type Restaurant {
  id: ID!
  name: String! @id @search(by: [hash])
  menu_items: [MenuItem!] @hasInverse(field: restaurant)
}

type MenuItem {
  id: ID!
  name: String! @search(by: [hash,regexp,term])
  description: String @search(by: [hash,regexp,term])
  restaurant: Restaurant!
}

and mutation:

mutation {
  addRestaurant(input:[
    {name:"R1"},
    {name:"R2"},
    {name:"R3"}
  ]) {
    numUids
  }
  addMenuItem(input:[
  {name:"Lasagne",restaurant:{name:"R1"}},
  {name:"Lasagne",restaurant:{name:"R2"}},
  {name:"Orange Juice",description:"1l bottle",restaurant:{name:"R1"}},
  {name:"Orange Juice",restaurant:{name:"R2"}},
  {name:"Apple Juice",restaurant:{name:"R2"}},
  {name:"Apple Juice",restaurant:{name:"R3"}},
  {name:"Steak",restaurant:{name:"R2"}}
    ]) {numUids}
}

When looking for a juice, I get expected results:

{queryMenuItem(filter:{name:{anyofterms:"juice"}})  {
  name
  restaurant {
    name
  }
}}
  "data": {
    "queryMenuItem": [
      {
        "name": "Apple Juice",
        "restaurant": {
          "name": "R3"
        }
      },
      {
        "name": "Orange Juice",
        "restaurant": {
          "name": "R1"
        }
      },
      {
        "name": "Orange Juice",
        "restaurant": {
          "name": "R2"
        }
      },
      {
        "name": "Apple Juice",
        "restaurant": {
          "name": "R2"
        }
      }
    ]
  },

When filtering for one restaurant:

{queryMenuItem(filter:{name:{anyofterms:"juice"}})  {
  name
  restaurant (filter:{name:{eq:"R2"}}){
    name
  }
}}

I get errors “Non-nullable field ‘restaurant’ (type Restaurant!) was not present in result from Dgraph. GraphQL error propagation triggered.”. It can be solver by using @cascade:

{queryMenuItem(filter:{name:{anyofterms:"juice"}}) @cascade {
  name
  description
  restaurant (filter:{name:{eq:"R2"}}){
    name
  }
}}

But then when I add a “description” (which can be null), I get no results.
Is it possible to get records with name “juice” from “R2” restaurant and with a (optionally null) description in GraphQL query?

2

Parameterized cascade just hit master. It should be in the next major release. This will allow you to specify what fields are required and what can be nullish.

1 Like
3

Great! Just for a reference, this works as expected:

{queryMenuItem(filter:{name:{anyofterms:"juice"}}) @cascade(fields:["restaurant"]) {
  name
  description
  restaurant (filter:{name:{eq:"R2"}}){
    name
  }
}}
1 Like