prisma.exists throws an error

[guatedude2]

Describe the bug
When calling prisma.exists on a type which is using "key" as the ID, prisma throws an Error.

To Reproduce
Steps to reproduce the behavior:

1. Create a type in the datamodel.graphql

type I18String {
  key: ID!
  string: String!
  language: Language!
}

2. Deploy and generate bindings
3. Call prisma.exists.I18String({ key: "123" })
4. See error

TypeError: Cannot read property 'length' of undefined
   at /Users/guatedude2/my-api/node_modules/prisma-binding/src/Prisma.ts:79:30

Expected behavior
Returns true or false

Versions (please complete the following information):

• OS: OS X Mohave
• prisma CLI: prisma/1.20.0 (darwin-x64) node-v10.4.0
• Prisma Server: 1.20.0
• prisma-binding, apollo-server, ts-node, typescript

Additional context

Doing my own investigation, seems like the issue is inside info.ts where buildExistsInfo, returns only a selection on id, which is hard-coded rather than what the model considers a primary key. In the case of I18String key is the ID but there is no unique primary key so it returns undefined and undefined.length throws the error.

I chose key as a non unique key because the key exists for each language (unique key + language) and I don't want prisma generating the id for me. So, I use key as the unique identifier where I set it to a human readable string e.g. "my-unique-key".

[maticzav]

Hey @guatedude2 👋,

I believe this is hardcoded in light of the current Prisma ID! implementation. Check out the following piece of documentation https://www.prisma.io/docs/data-model-and-migrations/data-model-knul/#id.

An ID value is a generated unique 25-character string based on cuid. Fields with ID values are system fields and just used internally, therefore it is not possible to create new fields with the ID type.

I hope this helps 🙂

[maticzav]

Closing in favour of #275