Can anyone think of a good way to programatically tell if a field is nullable at runtime? The data is in the schema and the types, but I need to look it up programatically at runtime, which doesn’t seem possible from what I can tell.

Hey @defrex 👋 Could you explain the use case for this?

I’m implementing Relay Connections on my graph with dynamic sort capabilities. As long as I encapsulate the

orderBy

values into the cursors this works fine. However, to calculate

hasNextPage

&

hasPreviousPage

I need to query “before” and “after” the current range for an arbitrary sort. That means something like this (for before, assuming

completedAt

is nullable)

{
  "where": {
    "AND": [
      {
        "createdAt": {
          "lt": "2020-08-20T14:42:27.681Z"
        }
      },
      {
        "OR": [
          {
            "completedAt": {
              "gt": "2020-08-20T14:42:27.683Z"
            }
          },
          {
            "completedAt": {
              "equals": null
            }
          }
        ]
      }
    ]
  },
  "orderBy": [
    {
      "completedAt": "desc"
    },
    {
      "createdAt": "asc"
    }
  ]
}

However, that same logic applied to a non-nullable field generates this.

{
  "where": {
    "AND": [
      {
        "completedAt": {
          "lt": "2020-08-20T14:42:27.681Z"
        }
      },
      {
        "OR": [
          {
            "createdAt": {
              "gt": "2020-08-20T14:42:27.683Z"
            }
          },
          {
            "createdAt": {
              "equals": null
            }
          }
        ]
      }
    ]
  },
  "orderBy": [
    {
      "completedAt": "asc"
    },
    {
      "createdAt": "desc"
    }
  ]
}

Which fails, since

createdAt

can’t be

null

.

Instead of a query, you could also try this:

import * as Prisma from '@prisma/client'
console.log(Prisma.dmmf.datamodel)

This will give you the entire datamodel and whether the fields are required or not

Amazing! Thanks so much, that’s just what I was hoping for.