Support Prisma's multiSchema feature via workaround

[duniul]

Context

Prisma supports multi-schemas via the multiSchema preview feature (https://www.prisma.io/docs/guides/other/multi-schema), but the schemas are not appended to the table names generated by prisma-kysely.

Sadly, @prisma/generator-helper doesn't expose the model schemas set via @@schema("schemaName"), so a workaround is needed for now. I've opened an issue for Prisma to fix this here: prisma/prisma#19987

Changes

• Add support for multiSchema and @@schema() attributes.
  • Uses @@mrleebo/prisma-ast to parse the datamodel separately and matches the schemas with the correct model. This is a workaround and is only needed until Prisma exposes the schema attribute on the DMMF.Model objects themselves.
  • Appends the schema name to the table names on the DB type (like what kysely-codegen does)
  • Does nothing if multiSchema is not enabled.
• Sort DB properties by table name instead of type name.
  • Especially noticeable when using multi-schemas, but makes sense without it too.
• Add changesets reflecting the changes.

Alternative solutions

• If you want to avoid third-party libs like @@mrleebo/prisma-ast then we could do it via bracket matching instead, though it's a bit more complex and potentially error prone.
• Wait for Prisma to expose the schema themselves, although that might take time.

Example output

Toggle example

prisma.schema (partial)

model Elephant {
  id   Int    @id
  name String

  @@map("elephants")
  @@schema("mammals")
}

model Eagle {
  id   Int    @id
  name String

  @@map("eagles")
  @@schema("birds")
}

Generated DB type before PR:

export type DB = {
  eagles: Eagle;
  elephants: Elephant;
};

Generated DB type after PR:

export type DB = {
  "birds.eagles": Eagle;
  "mammals.elephants": Elephant;
};

[valtyr]

@duniul This is awesome. Thank you so much for adding this functionality! The code looks good. I'm going to perform some sanity checks, and if they check out (which I suspect they will) I'll add this to the next release. 🇸🇪➕🇮🇸🟰🎉

[valtyr]

/snapshot

[github-actions]

📸 Snapshot

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Package name	Version	Git hash
prisma-kysely	0.0.0-snapshot-20230702140843

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