import { betterAuth } from 'better-auth'
import { drizzleAdapter } from 'better-auth-drizzle-adapter'
import { drizzle } from 'drizzle-orm/d1'
import * as schema from './schema'

const db = drizzle(env.DB, { schema })

export const auth = betterAuth({
  database: drizzleAdapter(db, { provider: 'sqlite' }),
  // ...
})

Array and JSON columns

Drizzle owns the encoding for every field Better Auth types as string[], number[] or json, so those columns must be declared as json mode. This is what createSchema generates:

scopes: text('scopes', { mode: 'json' }).$type<string[]>()   // sqlite, mysql
scopes: text('scopes').array()                               // pg

Upgrading to 1.2.0

string[] and number[] are unchanged: supportsArrays was already true, so the stored bytes and the values you read back are identical. Nothing to do.

Only json fields changed. Before 1.2.0, supportsJSON was provider-based, so on SQLite and MySQL Better Auth stringified them and the json-mode column stringified them again, storing "{\"a\":1}". Better Auth read that back correctly, so the bug was invisible unless you queried the column directly.

Rows written before 1.2.0 now decode to a string instead of an object. One idempotent statement unwraps them, skipping NULLs and rows that are already correct:

-- SQLite
UPDATE oauth_client
SET metadata = json_extract(metadata, '$')
WHERE metadata IS NOT NULL AND json_type(metadata) = 'text';

-- MySQL
UPDATE oauth_client
SET metadata = JSON_UNQUOTE(metadata)
WHERE metadata IS NOT NULL AND JSON_TYPE(metadata) = 'STRING';

Better Auth core (user, session, account, verification) has no json fields, so a plugin-free install has nothing to migrate. Run the statement once per json column your plugins declare; with oauthProvider that is only oauth_client.metadata.