Building SQL QueriesDocumentation

SQLite

The @databases/sqlite library provides an asynchronous, safe and convenient API for querying SQLite databases in node.js. Built on top of sqlite3.

N.B. you should only have one process connected to a given SQLite database at a time.

Usage

import connect, {sql} from '@databases/sqlite';
// or in CommonJS:
// const connect = require('@databases/sqlite');
// const {sql} = require('@databases/sqlite');

const db = connect();

db.query(sql`SELECT * FROM users;`).then(
  (results) => console.log(results),
  (err) => console.error(err),
);

For details on how to build queries, see Building SQL Queries

API

connect(fileName)

Create a database connection for a given database. You should only create one connection per database for your entire applicaiton. Normally this means having one module that creates and exports the connection pool.

In memory:

import connect from '@databases/sqlite';

const db = connect();

File system:

import connect from '@databases/sqlite';

const db = connect(FILE_NAME);

The DatabaseConnection inherits from DatabaseTransaction, so you call DatabaseConnection.query directly instead of having to create a transaction for every query. Since SQLite has very limited support for actual transactions, we only support running one transaction at a time, but multiple queries can be run in parallel. You should therefore only use transactions when you actually need them.

DatabaseConnection.query(SQLQuery): Promise<any[]>

Run an SQL Query and get a promise for an array of results.

DatabaseConnection.queryStream(SQLQuery): AsyncIterable<any>

Run an SQL Query and get an async iterable of the results. e.g.

for await (const record of db.queryStream(sql`SELECT * FROM massive_table`)) {
  console.log(result);
}

DatabaseConnection.tx(fn): Promise<T>

Executes a callback function as a transaction, with automatically managed connection.

A transaction wraps a regular task with additional queries:

  1. it executes BEGIN just before invoking the callback function

  2. it executes COMMIT, if the callback didn't throw any error or return a rejected promise

  3. it executes ROLLBACK, if the callback did throw an error or return a rejected promise

const result = await db.tx(async (transaction) => {
  const resultA = await transaction.query(sql`SELECT 1 + 1 AS a`);
  const resultB = await transaction.query(sql`SELECT 1 + 1 AS b`);
  return resultA[0].a + resultB[0].b;
});
// => 4

DatabaseConnection.dispose(): Promise<void>

Dispose the DatabaseConnection. Once this is called, any subsequent queries will fail.

MySQL Typed
Synchronous API