FlashQL Guide

Unlike the other clients, FlashQL is not a connector to an external database. It is the database itself, a full SQL runtime that runs in the same process as your app.

Use FlashQL when you want the database to run inside your application, in Node.js, the browser, a worker, or an edge runtime.

See the FlashQL Overview for architecture and capabilities.

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Setup

import { FlashQL } from '@linked-db/linked-ql/flashql';

const db = new FlashQL();
await db.connect();

const result = await db.query('SELECT 1::text AS result');
console.log(result.rows);

await db.disconnect();

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Configuration Shape

FlashQL is configured entirely at construction time and all parameters are optional:

Option	Type	Default	Purpose
dialect	'postgres' | 'mysql'	'postgres'	default SQL dialect
keyval	Keyval	null	enables persistence
getUpstreamClient	(origin) => client	null	resolves upstream sources
versionStop	string | object	null	boot at a historical point
overwriteForward	boolean	false	allow branching from history
autoSync	boolean	true	run sync on connect

Example:

const keyval = new IndexedDBKV({ path: ['my-app'] });
const upstream = new EdgeClient({ url: remoteUrl });

const db = new FlashQL({
  dialect: 'mysql',
  keyval,
  getUpstreamClient: () => upstream,
});

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Persistence

FlashQL supports persistence via the keyval parameter.

See Persistence.

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Upstream Connections

FlashQL connects to external databases via the getUpstreamClient() callback.

See Federation, Materialization, and Sync.

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Realtime Notes

Realtime queries, WAL subscriptions, and sync are built into the runtime. No database-level setup is required.

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Additional Reading

If you want to learn about...	Go to...
the common application-facing methods	API
the broader FlashQL architecture	FlashQL Overview