Sequelize Connection String and Configuration

Sequelize Connection Formats

Sequelize, one of the most popular Node.js ORMs, supports both URI string and object-based configuration.

URI String

const { Sequelize } = require('sequelize');

const sequelize = new Sequelize('postgresql://user:pass@localhost:5432/mydb');

Object Configuration

const sequelize = new Sequelize('mydb', 'user', 'password', {
  host: 'localhost',
  port: 5432,
  dialect: 'postgres',
  logging: false,
  pool: {
    max: 10,
    min: 2,
    acquire: 30000,
    idle: 10000,
  },
});

Dialect-Specific URIs

PostgreSQL

postgres://user:pass@host:5432/database

MySQL

mysql://user:pass@host:3306/database

SQLite

const sequelize = new Sequelize({
  dialect: 'sqlite',
  storage: './database.sqlite',
});

SQLite in Sequelize uses storage instead of a URI.

MSSQL

mssql://user:pass@host:1433/database

SSL Configuration

Sequelize passes SSL options through dialectOptions:

const sequelize = new Sequelize('postgres://user:pass@host/db', {
  dialectOptions: {
    ssl: {
      require: true,
      rejectUnauthorized: true,
      ca: fs.readFileSync('/path/to/ca.pem').toString(),
    },
  },
});

Connection Pool Options

Option	Purpose	Default
pool.max	Maximum connections	5
pool.min	Minimum connections	0
pool.acquire	Max time (ms) to get connection	60000
pool.idle	Max time (ms) connection can be idle	10000
pool.evict	Interval (ms) to remove idle connections	1000

Environment Variable Pattern

A common pattern is to use DATABASE_URL in production and explicit config in development:

const sequelize = process.env.DATABASE_URL
  ? new Sequelize(process.env.DATABASE_URL, {
      dialectOptions: { ssl: { require: true } },
    })
  : new Sequelize('mydb', 'root', '', {
      host: 'localhost',
      dialect: 'mysql',
    });