Your First Project

Quick Start showed one file. A real project uses a config file and migrations. This guide builds that scaffold.

Project layout

• Directorymy-app/

  • mountsqli.config.ts
  • Directorysrc/

    • db.ts
    • main.ts
  • package.json

1. Define tables

src/tables.ts

import { defineTable, int, text, timestamp } from "@mountsqli/core";

export const posts = defineTable("posts", {
  id: int().pk(),
  title: text().notNull(),
  body: text(),
  createdAt: timestamp().notNull().defaultNow(),
});

2. Write the config

mountsqli.config.ts is the single source of truth. The Db type is derived from it — never hand-rolled.

mountsqli.config.ts

import { defineConfig } from "@mountsqli/core";
import { posts } from "./src/tables";

export default defineConfig({
  driver: "sqlite",
  url: "./app.db", // file URL persists _mount_migrations
  tables: [posts],
});

3. Derive the typed Db

src/db.ts

import { mountsqli, type DbFromConfig } from "@mountsqli/core";
import config from "../mountsqli.config";

export const db = mountsqli(config);
export type AppDb = DbFromConfig<typeof config>;

No manual tuples

DbFromConfig<typeof config> infers the table list from the config. You never write a tuple of table types by hand.

4. Generate and apply migrations

npx mountsqli migrate generate
npx mountsqli migrate apply

This creates posts and records the step in _mount_migrations.

5. Use it

src/main.ts

import { db, posts } from "./db";

await db.from(posts).insert({ title: "Hello", body: "First post" });

const all = await db.from(posts).all();
console.log(all);

Mermaid: project flow

flowchart TD
  A[tables.ts] --> B[mountsqli.config.ts]
  B --> C[db.ts: typed Db]
  C --> D[migrate generate]
  D --> E[_mount_migrations]
  C --> F[your app queries]

Best practices

• Keep tables in their own module and import them into the config.
• Commit mountsqli.config.ts; it is your schema of record.
• Use a file URL (not :memory:) so migrations persist between runs.

Common mistakes

• Editing the table in code but forgetting migrate generate — the live DB drifts.
• Deriving Db by hand instead of DbFromConfig — you lose type accuracy.

Related

• Migrations → How Migrations Work — diff, generate, apply.
• Core Concepts — the config-as-source-of-truth model.
• CLI → Commands — every mountsqli subcommand.