Prisma Migrate fails with defaults on `Json` when using SQLite

[emmatown]

Bug description

Prisma generates invalid SQL when using the Json type with a default value.

Severity

⚠️ Major: Breaks core functionality (e.g., migrations fail)

Reproduction

1. Create a schema.prisma with the contents from the prisma schema section of this issue
2. Run prisma db push
3. Receive the error shown in the logs section of this issue

https://codesandbox.io/p/devbox/prisma-json-default-reproduction-6gqm29?file=%2Fschema.prisma%3A4%2C1

Expected vs. Actual Behavior

I expected Prisma to add the default correctly (in quotes). Instead I got an error from SQLite because Prisma generated invalid SQL.

Frequency

Consistently reproducible

Does this occur in development or production?

Only in development (e.g., CLI tools, migrations, Prisma Studio)

Is this a regression?

It hasn't worked in a previous version, it has been broken since support for Json in SQLite was added

Workaround

Avoid using default values with the Json scalar

Prisma Schema & Queries

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "sqlite"
  url      = "file:./dev.db"
}

model A {
  id Int  @id @default(autoincrement())
  b  Json @default("{\"something\": true}")
}

Logs & Debug Info

This is the result from running prisma db push

Environment variables loaded from .env
Prisma schema loaded from schema.prisma
Datasource "db": SQLite database "dev.db" at "file:./dev.db"
Error: SQLite database error
unrecognized token: "{" in CREATE TABLE "A" (
    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
    "b" JSONB NOT NULL DEFAULT {"something": true}
) at offset 103
   0: sql_schema_connector::apply_migration::migration_step
           with step=CreateTable { table_id: TableId(0) }
             at schema-engine/connectors/sql-schema-connector/src/apply_migration.rs:21
   1: sql_schema_connector::apply_migration::apply_migration
             at schema-engine/connectors/sql-schema-connector/src/apply_migration.rs:10
   2: schema_core::state::SchemaPush
             at schema-engine/core/src/state.rs:504

Environment & Setup

• OS: macOS
• Database: SQLite
• Node.js version: v22.13.1

Prisma Version

prisma                  : 6.4.1
@prisma/client          : 6.4.1
Computed binaryTarget   : darwin-arm64
Operating System        : darwin
Architecture            : arm64
Node.js                 : v22.13.1
TypeScript              : 4.9.5
Query Engine (Node-API) : libquery-engine a9055b89e58b4b5bfb59600785423b1db3d0e75d (at node_modules/.pnpm/@prisma+engines@6.4.1/node_modules/@prisma/engines/libquery_engine-darwin-arm64.dylib.node)
Schema Engine           : schema-engine-cli a9055b89e58b4b5bfb59600785423b1db3d0e75d (at node_modules/.pnpm/@prisma+engines@6.4.1/node_modules/@prisma/engines/schema-engine-darwin-arm64)
Schema Wasm             : @prisma/prisma-schema-wasm 6.4.0-29.a9055b89e58b4b5bfb59600785423b1db3d0e75d
Default Engines Hash    : a9055b89e58b4b5bfb59600785423b1db3d0e75d
Studio                  : 0.509.0

[nurul3101]

Hey @emmatown 👋

You need to enclose it with double-quotes inside the @default attribute like this:

https://www.prisma.io/docs/orm/prisma-client/special-fields-and-types/working-with-json-fields#how-to-set-a-default-value-for-json-fields

Does the error occur if you wrap the value true with double quotes?

[nurul3101]

I just tried invoking npx prisma db push command with the example from docs:

model A {
  id Int  @id @default(autoincrement())
  b  Json @default("{ \"hello\": \"world\" }")
}

And I still got the error:

Error: SQLite database error
unrecognized token: "{" in CREATE TABLE "new_A" (
    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
    "b" JSONB NOT NULL DEFAULT { "hello": "world" }
) at offset 107
   0: sql_schema_connector::apply_migration::migration_step
           with step=RedefineTables([RedefineTable { added_columns: [TableColumnId(1)], added_columns_with_virtual_defaults: [], dropped_columns: [], dropped_primary_key: false, column_pairs: [(MigrationPair { previous: TableColumnId(0), next: TableColumnId(0) }, ColumnChanges { type_change: None, changes: BitFlags<ColumnChange>(0b0) }, None)], table_ids: MigrationPair { previous: TableId(0), next: TableId(0) } }])
             at schema-engine/connectors/sql-schema-connector/src/apply_migration.rs:21
   1: sql_schema_connector::apply_migration::apply_migration
             at schema-engine/connectors/sql-schema-connector/src/apply_migration.rs:10
   2: schema_core::state::SchemaPush
             at schema-engine/core/src/state.rs:504

[Flysky12138]

unrecognized token: "{" in CREATE TABLE ...

model A {
  id Int  @id @default(autoincrement())
  b  Json @default("{}")
}

fix

model A {
  id Int  @id @default(autoincrement())
  b  Json @default("\"{}\"")
}

[recsater]

[tuliren]

@default(""{}"")

I am using Prisma 6.5, and I can confirm that this workaround fixes the migration. However, when this bug is fixed, will the fix be backward compatible with this workaround?

[memorw]

@default(""{}"")

If use this, you will get "{}". It is a string, but not object :(

[dcousens]

@nurul3101 single quotes are required when printing the default JSON value in SQL, but none are output by Prisma.

"b" JSONB NOT NULL DEFAULT {"something": true}

Should be

"b" JSONB NOT NULL DEFAULT '{"something": true}'

We can't do this using our Prisma schema, as Prisma enforces that the value is valid JSON (no single quotes).