Configuration

Create typed-sql.config.ts in the application root. The config selects the dialect, schema provider, generated output, TypeScript projects, and type policy used by both inference and runtime decoding.

PostgreSQL

import { defineConfig } from "@typed-sql/core";
import { postgres, typePolicy } from "@typed-sql/postgres";
import { pg } from "@typed-sql/postgres/pg";

export default defineConfig({
  dialect: postgres({ typePolicy }),
  schema: {
    file: "src/generated/db/schema.json",
    provider: pg({
      connectionString: () => process.env.DATABASE_URL!,
      schemas: ["public"],
      typePolicy,
    }),
  },
  outDir: "src/generated/db",
  projects: ["tsconfig.json"],
  typePolicy,
  compiler: {
    maxStructuralVariants: 64,
  },
});

MySQL

import { defineConfig } from "@typed-sql/core";
import { mysql, typePolicy } from "@typed-sql/mysql";
import { mysql2 } from "@typed-sql/mysql/mysql2";

export default defineConfig({
  dialect: mysql({ typePolicy }),
  schema: {
    file: "src/generated/db/schema.json",
    provider: mysql2({
      connectionUri: () => process.env.DATABASE_URL!,
      schemas: ["app"],
      typePolicy,
    }),
  },
  outDir: "src/generated/db",
  projects: ["tsconfig.json"],
  typePolicy,
  compiler: {
    maxStructuralVariants: 64,
  },
});

Generate and check

pnpm exec typed-sql generate
pnpm exec typed-sql check --file src/query.ts --project tsconfig.json
pnpm exec typed-sql drift

generate introspects the configured database and writes deterministic schema metadata. check analyzes SQL and asks TypeScript to validate the inferred overlay. drift compares the committed snapshot and type-policy hash with the live database.

Connection strings stay in the config callback or environment. They are not written to generated files. Commit the generated snapshot so schema and type-policy changes are reviewable.

The same typePolicy must be passed to the dialect, schema provider, and runtime adapter. This keeps the inferred TypeScript type aligned with the value returned by the driver.