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9 Greatest JavaScript and TypeScript ORMs for 2021 – SitePoint

This text will briefly clarify what object relational mapping (ORM) is, what an ORM library is, and why it’s best to think about using one along with your subsequent JavaScript undertaking. We’ll additionally enable you consider the very best JavaScript and TypeScript ORM libraries based mostly in your wants as a undertaking developer and maintainer.

We’ll take a look at every of the next instruments:

Object Relational Mapping

Object relational mapping may appear complicated, however its function is to make your life as a programmer simpler. To get information out of a database, it is advisable to write a question. Does that imply you need to study SQL? Nicely, no. Object relational mapping makes it attainable so that you can write queries within the language of your alternative.

Object relational mapping is a way for changing a database question outcome into entity class cases. An entity is just an object wrapper for a database desk. It incorporates attributes which might be mapped to columns of a database desk. Entity cases have methods of performing CRUD operations and have assist for extra features that include customized logic similar to validation and information encryption.

For those who’re constructing a small undertaking, putting in an ORM library isn’t required. Utilizing SQL statements to drive your utility must be enough. An ORM is kind of useful for medium- to large-scale initiatives that supply information from lots of of database tables. In such a state of affairs, you want a framework that means that you can function and preserve your utility’s information layer in a constant and predictable manner.

Entity courses are the constructing blocks of enterprise purposes, as they’re designed to encapsulate logic for implementing enterprise guidelines. A enterprise rule is outlined to make sure that an automatic course of solely executes throughout the boundaries of a enterprise coverage. Examples of enterprise guidelines embody:

  • buyer reductions
  • mortgage approvals
  • gross sales commissions
  • delivery and tax calculations

ORM Libraries

Object relational mapping is usually undertaken with assist of a library. The time period ORM mostly refers to an precise ORM library — an object relational mapper — that carries out the work of object relational mapping for you.

Typically enterprise guidelines require the execution of a number of SQL statements that must run in batches. If a single SQL assertion fails, it will probably depart the database in an inconsistent state. Most ORM libraries assist a function often known as Transactions, which prevents such an incidents from occurring. If an SQL assertion fails to run throughout the context of a transaction, all different SQL statements that had efficiently executed inside that batch are reversed by way of an operation often known as roll again.

Therefore, utilizing an ORM library to construct your information layer helps be certain that the database will all the time stay in a constant state. ORM libraries usually include many extra important options, similar to:

  • question builders
  • migration scripts
  • a CLI device for producing boilerplate code
  • a seeding function for pre-populating tables with check information

On this article, I’ll present snippets on how every ORM library does:

  • preliminary setup and configuration
  • fundamental CRUD operations
  • advance question operations

I’ve additionally included necessary data such because the launch dates, variety of customers and hyperlinks to documentation, and assist channels if out there. I’ll even be discussing necessary points relating to question efficiency, library upkeep and structure philosophy that it’s best to weigh closely when making your determination.

I’ve ordered the listing based mostly on launch date from the earliest to the most recent. I’ve break up the listing into two sections based mostly on the first supported language: JavaScript and TypeScript.

Earlier than we start our analysis, let’s first check out Knex.js, a preferred SQL Question Builder that comes already built-in with a lot of ORM libraries listed right here. Knex.js may be very versatile and infrequently performs higher than a few of the ORM libraries which have their very own built-in implementation of a Question Builder. Think about this a bonus when selecting an ORM library that makes use of Knex.js as its basis.

Knex.js: SQL Question Builder

  • Launch: Dec, 2012
  • Web site
  • GitHub: Utilized by 158.6k
  • Databases: Postgres, MSSQL, MySQL, MariaDB, SQLite3, Oracle, and Amazon Redshift

Knex.js is at the moment probably the most mature JavaScript SQL Question builder that may run in each Node.js and the browser (by way of webpack or Browserify). It’s able to producing extremely performant SQL queries which might be on par with manually written SQL statements.

So what’s a Question Builder?

It’s merely an API that gives a set of features that may be chained collectively to kind a question. Right here’s an instance:

knex({ a: 'desk', b: 'desk' })
    aTitle: 'a.title',
    bTitle: 'b.title'
  .whereRaw('?? = ??', ['a.column_1', 'b.column_2'])

SQL Output:
choose `a`.`title` as `aTitle`, `b`.`title` as `bTitle` from `desk`
as `a`, `desk` as `b` the place `a`.`column_1` = `b`.`column_2`

This begs the query of why ought to one use a Question Builder as an alternative of writing uncooked SQL statements. I’ll offer you 4 causes:

  • It helps you summary your code out of your database’s SQL dialect, making switching simpler.
  • It eliminates, or drastically reduces, the possibilities of SQL injection assaults in your utility.
  • It permits simple constructing of queries with dynamic situations.
  • It comes with further options and CLI instruments for performing database growth operations.

These options embody:

  • connection pooling
  • callback and Promise interfaces
  • stream interface
  • transaction assist
  • schema assist
  • migration
  • seeding

Putting in it in your utility requires you to put in the Knex.js package deal, together with the driving force of the database you’re utilizing:

$ npm set up knex --save

$ npm set up pg
$ npm set up sqlite3
$ npm set up mysql
$ npm set up mysql2
$ npm set up oracledb
$ npm set up mssql

Right here’s an instance of setup code:

const knex = require('knex')({
  consumer: 'mysql',
  connection: {
    host : '',
    person : 'your_database_user',
    password : 'your_database_password',
    database : 'myapp_test'

knex.schema.createTable('customers', operate (desk) {

create desk `customers` (`id` int unsigned not null auto_increment main key, `title` varchar(255),
`created_at` datetime, `updated_at` datetime)

Right here’s an instance of a fundamental question:

knex('customers').the place({
  first_name: 'Take a look at',
  last_name:  'Person'

choose `id` from `customers` the place `first_name` = 'Take a look at' and `last_name` = 'Person'

Uncooked SQL statements are additionally supported. Right here’s an instance of a posh question:

const subcolumn = knex.uncooked('choose avg(wage) from worker the place dept_no = e.dept_no')
.wrap('(', ') avg_sal_dept');

knex.choose('e.lastname', 'e.wage', subcolumn)
.from('worker as e')
.whereRaw('dept_no = e.dept_no')

choose `e`.`lastname`, `e`.`wage`, (choose avg(wage) from worker the place dept_no = e.dept_no)
avg_sal_dept from `worker` as `e` the place dept_no = e.dept_no

Knex.js additionally helps TypeScript, which is nice, because it means that you can write code like this:

import { Knex, knex } from 'knex'

interface Person {
  id: quantity;
  age: quantity;
  title: string;
  energetic: boolean;
  departmentId: quantity;

const config: Knex.Config = {
  consumer: 'sqlite3',
  connection: {
    filename: './information.db',

const knexInstance = knex(config);

strive {
  const customers = await knex<Person>('customers').choose('id', 'age');
} catch (err) {

Within the above TypeScript instance, Knex.js is nearly appearing like an ORM. Nonetheless, entity object cases aren’t being created. As a substitute, the interface definition is getting used to create JavaScript objects with type-safe properties.

Do word a lot of ORM libraries listed on this article use Knex.js underneath the hood. These embody:

  • Bookshelf
  • Objection.js
  • MikroORM

ORM libraries usually present further options on high of Knex.js. Let’s take a look at them within the subsequent part.

JavaScript ORM Libraries

On this class, all libraries listed below are written in JavaScript and might run straight in Node.js. TypeScript assist is supplied both by way of built-in varieties or by way of @varieties/node definitions package deal. In order for you first-class assist for TypeScript initiatives, it’s best to skip to the TypeScript ORM Libraries part.

Within the information entry layer, there are two common architectural patterns which might be used:

With the Knowledge Mapper sample, entity courses are pure and solely include attributes. CRUD operations and enterprise guidelines are applied in containers often known as repositories. Right here’s an instance:

const repository = connection.getRepository(Person);.

const person = new Person();
person.firstName = "Timber";

const allUsers = await;

With Lively report sample, logic for CRUD operations and enterprise guidelines are applied inside entity courses. Right here’s an identical instance implementation of the above:

const person = new Person();
person.firstName = "Timber";

const allUsers = await;

There are professionals and cons of utilizing both sample. These patterns had been named by Martin Fowler in his 2003 guide Patterns of Enterprise Utility Structure. You need to test the guide out if you need extra detailed data on the topic. Most ORM libraries listed on this article assist one or each patterns.

Let’s begin them now.


  • Launch: July 2010
  • Web site
  • GitHub: utilized by 271k
  • Slack
  • Databases: Postgres, MySQL, MariaDB, SQLite and Microsoft SQL Server

Sequelize is a really mature and common Node.js ORM library with wonderful documentation containing nicely defined code examples. It helps lots of the information layer options that we’ve already talked about earlier than in earlier libraries. Not like Bookshelf, it has its personal Question Builder which performs simply in addition to Knex.js

Putting in the library is kind of easy, and the database driver is kind of simple:

$ npm i sequelize 

$ npm i pg pg-hstore 
$ npm i mysql2
$ npm i mariadb
$ npm i sqlite3
$ npm i tedious 

Beneath is an instance of the setup code together with examples of CRUD and fundamental question statements:

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

const sequelize = new Sequelize('database', 'username', 'password', {
  host: 'localhost',

const Person = sequelize.outline('Person', {
  firstName: {
    kind: DataTypes.STRING,
    allowNull: false
  lastName: {
    kind: DataTypes.STRING
}, {

const jane = Person.construct({ firstName: "Jane", lastName: "Doe" });

const jane = await Person.create({ firstName: "Jane", lastName: "Doe" });

const customers = await Person.findAll();
console.log(customers.each(person => person instanceof Person)); 
console.log("All customers:", JSON.stringify(customers, null, 2));

The next is an instance of how a posh question is written:

  the place: sequelize.the place(sequelize.fn('char_length', sequelize.col('content material')), 7)

  the place: {
    [Op.or]: [
      sequelize.where(sequelize.fn('char_length', sequelize.col('content')), 7),
        content: {
          []: 'Howdy%'
        [Op.and]: [
          { status: 'draft' },
          sequelize.where(sequelize.fn('char_length', sequelize.col('content')), {
            []: 10

Within the final complicated question instance, the SQL output was:

FROM "posts" AS "submit"
  char_length("content material") = 7
  "submit"."content material" LIKE 'Howdy%'
  OR (
    "submit"."standing" = 'draft'
    char_length("content material") > 10

Sequelize helps uncooked SQL statements, which provides builders the flexibleness to jot down complicated and extremely performant SQL statements. The outcomes can be mapped to object entity cases. Right here’s an instance:

const initiatives = await sequelize.question('SELECT * FROM initiatives', {
  mannequin: Tasks,
  mapToModel: true 

The principle draw back of Sequelize is that growth has slowed down and that points have piled up with out being resolved. Fortuitously, one of many maintainers has introduced that the library will get the eye it deserves from 2021. Do word that each one ORM library initiatives on this article are open supply and that they do need assistance from builders to make them higher.


  • Launch: March, 2013
  • Web site
  • GitHub: Utilized by 22.4k
  • Plugins
  • Databases : PostgreSQL, MySQL, and SQLite3

Bookshelf is without doubt one of the oldest and most elementary ORM JavaScript library now we have out there. It’s constructed on high of Knex.js SQL Question Builder, and it takes plenty of concepts from the Knowledge Mapper sample. It supplies further options, similar to:

  • keen and nested-eager relation loading
  • polymorphic associations
  • assist for one-to-one, one-to-many, and many-to-many relations.

It’s unlucky there’s no built-in assist for validation. Nonetheless, it may be applied in code by way of a third-party library similar to checkit.

Putting in Bookshelf in your undertaking is as follows:

$ npm set up knex
$ npm set up bookshelf

$ npm set up pg
$ npm set up mysql
$ npm set up sqlite3

Setup code seems to be like this:

const knex = require('knex')({
  consumer: 'mysql',
  connection: {
    host     : '',
    person     : 'your_database_user',
    password : 'your_database_password',
    database : 'myapp_test',
    charset  : 'utf8'
const bookshelf = require('bookshelf')(knex)

const Person = bookshelf.mannequin('Person', {
  tableName: 'customers',
  posts() {
    return this.hasMany(Posts)

const Submit = bookshelf.mannequin('Submit', {
  tableName: 'posts',
  tags() {
    return this.belongsToMany(Tag)

const Tag = bookshelf.mannequin('Tag', {
  tableName: 'tags'

new Person({id: 1}).fetch({withRelated: ['posts.tags']}).then((person) => {
}).catch((error) => {

You’ll must search for the Knex.js documentation to see the way to carry out queries and CRUD transactions. Bookshelf’s documentation doesn’t cowl this.

Curiously, Strapi, a headless CMS, makes use of Bookshelf as its default database connector. Nonetheless, it’s price noting the next points:

  • the documentation will not be significantly useful
  • on the time of writing, the library hadn’t been up to date for 5 months


Waterline is the default ORM utilized by Sails.js, a Node.js framework. When utilizing Sails.js to develop your undertaking, the quantity of code it is advisable to write to construct your personal database API is drastically lowered. That is achieved utilizing convention-over-configuration philosophy and the Blueprints API that incorporates boilerplate code for accessing the database and performing CRUD features. As well as, Sails.js supplies a command-line interface that helps builders generate API routes, carry out migrations and different information layer features. Typescript assist is offered by way of the Typed definitions package deal.

On this article, we’re going to imagine you’d wish to use the Waterline ORM as a standalone, which is feasible. Let’s take a look at the way to set up and set it up.

Set up requires you to put in the Waterline library, then one of many database adapters:

$ npm set up --save waterline

$ npm set up --save sails-mysql
$ npm set up --save-dev sails-disk

Right here’s a partial pattern of the setup code:

const Waterline = require('waterline');
const sailsDiskAdapter = require('sails-disk');
const waterline = new Waterline();

const userCollection = Waterline.Assortment.lengthen({
  identification: 'person',
  datastore: 'default',
  primaryKey: 'id',

  attributes: {
    id: {
        kind: 'quantity',
        autoMigrations: {autoIncrement: true}
    firstName: {kind:'string'},
    lastName: {kind:'string'},

    pets: {
      assortment: 'pet',
      by way of: 'proprietor'


Right here’s a partial pattern of some CRUD code:

(async ()=>{
    var person = await Person.create({
      firstName: 'Neil',
      lastName: 'Armstrong'

    var pet = await Pet.create({
      breed: 'beagle',
      kind: 'canine',
      title: 'Astro',

    var customers = await'pets');

Right here’s a pattern of a fundamental question code:

var thirdPageOfRecentPeopleNamedMary = await{
  the place: { title: 'mary' },
  skip: 20,
  restrict: 10,
  type: 'createdAt DESC'

In terms of dealing with complicated queries, the documentation appears to be lacking that half. For those who plan on utilizing Sails.js, utilizing Waterline ORM is a no brainer. However as a standalone, the ORM library faces the next points:

  • Documentation is blended in with Sails.js documentation.
  • On the time of writing, the library package deal hadn’t been up to date in 9 months.


  • Launch: April 2015
  • Web site
  • GitHub: Utilized by 5.7k
  • Plugins
  • Databases : SQLite3, Postgres and MySQL (together with all Knex.js supported databases)

Objection.js is a minimal Node.js ORM library designed to remain out of your manner and make is simple to entry SQL databases. On this class, Objection.js is the youngest, and it seems to defeat many arguments which have been raised towards using ORM libraries.

The Objection.js documentation is great. It’s nicely written, as you’ll be able to simply discover clear directions for constructing your utility’s information layer. The syntax is clear and straightforward to know. It’s constructed on high of Knex.js, and has official built-in assist for TypeScript. It has about every part you want in an ORM.

Wanting on the numbers, it’s fairly stunning Objection.js isn’t as common at it must be. ORM libraries similar to Sequelize and TypeORM do provide many extra options, which can clarify their recognition. Nonetheless, I feel the set of options the Objection.js group determined to go together with is ideal for an open-source library. It means fewer bugs happen over time, and the small group are capable of resolve them in good time. You possibly can see proof of this by wanting on the points tab, which had about 50 unresolved points on the time of writing.

In distinction, Sequelize and TypeORM, that are larger in phrases options, have sadly generated a large backlog for his or her maintainers. Presently, every have 1,000+ points that haven’t been resolved and there doesn’t appear to be a rise within the variety of maintainers contributing to the undertaking.

For those who’re having any doubt about choosing this library, take a look at this testimonals hyperlink.

Let’s check out the set up steps and a few pattern code. To get began, you’ll want to put in Objection.js, Knex.js and one of many database adapters:

npm set up objection knex

npm set up pg
npm set up sqlite3
npm set up mysql
npm set up mysql2

The setup code is so easy it hardly wants any rationalization:

const { Mannequin } = require('objection');
const Knex = require('knex');

const knex = Knex({
  consumer: 'sqlite3',
  useNullAsDefault: true,
  connection: {
    filename: 'instance.db'


class Particular person extends Mannequin {
  static get tableName() {
    return 'individuals';

  static get relationMappings() {
    return {
      youngsters: {
        relation: Mannequin.HasManyRelation,
        modelClass: Particular person,
        be a part of: {
          from: '',
          to: 'individuals.parentId'

async operate createSchema() {
  if (await knex.schema.hasTable('individuals')) {

  await knex.schema.createTable('individuals', desk => {

async operate most important() {
  const sylvester = await Particular person.question().insertGraph({
    firstName: 'Sylvester',

    youngsters: [
        firstName: 'Sage'
        firstName: 'Sophia'

  console.log('created:', sylvester);

  const sylvesters = await Particular person.question()
    .the place('firstName', 'Sylvester')

  console.log('sylvesters:', sylvesters);

  .then(() => most important())
  .then(() => knex.destroy())
  .catch(err => {
    return knex.destroy();

Right here’s an instance of fundamental question:

const particular person = await Particular person.question().findById(1);

const middleAgedJennifers = await Particular person.question()
  .choose('age', 'firstName', 'lastName')
  .the place('age', '>', 40)
  .the place('age', '<', 60)
  .the place('firstName', 'Jennifer')

The SQL output for the essential question:

choose "individuals".* from "individuals" the place "individuals"."id" = 1

choose "age", "firstName", "lastName"
from "individuals"
the place "age" > 40
and "age" < 60
and "firstName" = 'Jennifer'
order by "lastName" asc

Right here’s an instance of a posh question:

const individuals = await Particular person.question()
  .choose('individuals.*', 'dad or mum.firstName as parentFirstName')
  .innerJoin('individuals as dad or mum', 'individuals.parentId', 'dad or')
  .the place('individuals.age', '<', Particular person.question().avg('individuals.age'))
      .whereColumn('', 'animals.ownerId')


The SQL output for the complicated question:

choose "individuals".*, "dad or mum"."firstName" as "parentFirstName"
from "individuals"
interior be a part of "individuals"
  as "dad or mum"
  on "individuals"."parentId" = "dad or mum"."id"
the place "individuals"."age" < (
  choose avg("individuals"."age")
  from "individuals"
and exists (
  choose 1
  from "animals"
  the place "individuals"."id" = "animals"."ownerId"
order by "individuals"."lastName" asc

Along with the options Knex.js already supplies, Objection.js has:

  • official TypeScript assist
  • assist for lifecycle hooks
  • built-in validation assist utilizing JSON Schema syntax
  • plugins

The library may be very nicely maintained. For SQL databases, Objection.js seems to be the very best ORM library on your JavaScript utility. Sadly, it doesn’t assist NoSQL databases. However the subsequent library we function does assist NoSQL databases.


For those who plan on utilizing MongoDB as your database, then Mongoose is probably going going to be your ORM of alternative. It’s at the moment the most well-liked ORM library within the Node.js world. Mongoose makes use of schema syntax to outline fashions. Its function listing contains:

  • built-in kind casting
  • validation
  • question constructing
  • hooks by way of middleware

Mongoose solely helps MongoDB, so set up solely requires one package deal:

npm set up mongoose

Beneath is an instance of the setup code:

const mongoose = require('mongoose');
mongoose.join('mongodb://localhost/check', {useNewUrlParser: true, useUnifiedTopology: true});

const kittySchema = new mongoose.Schema({
   title: {
    kind: String,
    required: true
const Kitten = mongoose.mannequin('Kitten', kittySchema);

const fluffy = new Kitten({ title: 'fluffy' }); (err, fluffy) {
    if (err) return console.error(err);
    console.log(fluffy.title, 'saved!')

There are two methods of defining queries in Mongoose. Beneath are each examples:

Particular person.
    occupation: /host/,
    '': 'Ghost',
    age: { $gt: 17, $lt: 66 },
    likes: { $in: ['vaporizing', 'talking'] }
  type({ occupation: -1 }).
  choose({ title: 1, occupation: 1 }).

Particular person.
  discover({ occupation: /host/ }).
  the place('').equals('Ghost').
  the place('age').gt(17).lt(66).
  the place('likes').in(['vaporizing', 'talking']).
  choose('title occupation').

In fact, there’s no uncooked SQL possibility, since MongoDB is a NoSQL database. MongoDB additionally doesn’t assist transactions. If that’s necessary on your undertaking, you’ll want to stay with SQL databases.

One key benefit of Mongoose over all different open-source ORM libraries listed right here is that it’s growth is sponsored by the Tidelift platform. This implies safety points are recognized and patched early.

One draw back is that Mongoose doesn’t formally assist TypeScript. Unofficially, you should utilize TypeScript, however it should take a bit of additional work to take care of your fashions. Fortuitously, the following ORM library we’ll take a look at addresses this concern.

TypeScript ORM Libraries

On this class, all libraries listed right here present first-class assist for TypeScript initiatives. You should use them in JavaScript initiatives, however documentation is generally written for TypeScript code.


Typegoose is a “wrapper” for simply writing Mongoose fashions with TypeScript. This library solves the issue of getting to take care of a separate Mongoose mannequin and a TypeScript interface. With Typegoose, you solely must outline your mannequin schema utilizing the Typegoose interface.

Underneath the hood, it makes use of the Replicate and reflect-metadata API to retrieve the forms of the properties, so redundancy could be considerably lowered.

Putting in Typegoose in your initiatives requires a number of packages:

npm i -s @typegoose/typegoose 
npm i -s mongoose 
npm i -D @varieties/mongoose 

Beneath is an instance of a Mongoose mannequin written in JavaScript:

const kittenSchema = new mongoose.Schema({
  title: String

const Kitten = mongoose.mannequin('Kitten', kittenSchema);

let doc = await Kitten.create({ title: 'Kitty' });

Beneath is identical mannequin written in TypeScript utilizing Typegoose library:

class KittenClass {
  public title?: string;

const Kitten = getModelForClass(KittenClass);

let doc = await Kitten.create({ title: 'Kitty' });

The next code pattern reveals the setup course of and the way to execute CRUD instructions:

import { prop, getModelForClass } from '@typegoose/typegoose';
import * as mongoose from 'mongoose';

class Person {
  public title?: string;

  @prop({ kind: () => [String] })
  public jobs?: string[];

const UserModel = getModelForClass(Person); 

(async () => {
  await mongoose.join('mongodb://localhost:27017/', { useNewUrlParser: true, useUnifiedTopology: true, dbName: "check" });

  const { _id: id } = await UserModel.create({ title: 'JohnDoe', jobs: ['Cleaner'] } as Person); 
  const person = await UserModel.findById(id).exec();


Since Typegoose is just a TypeScript wrapper for an ORM library, you’ll have to take a look at the Mongoose documentation to see the way to carry out CRUD duties.


  • Launch : Feb 21, 2016
  • Web site
  • GitHub: Utilized by 71.8k
  • Slack
  • Databases : MySQL, MariaDB, Postgres, CockroachDB, SQLite, Microsoft SQL Server, Oracle, SAP Hana, sql.js and MongoDB

TypeORM is at the moment the most well-liked ORM library constructed for TypeScript initiatives. It may run on many platforms, together with:

  • Node.js
  • the browser
  • on cellular — Cordova, PhoneGap, Ionic, React Native and NativeScript
  • Electron

The library additionally helps each Lively Document and Knowledge Mapper patterns, permitting builders to construct high-quality, scalable and maintainable database-driven purposes. It’s extremely influenced by different ORMs similar to Hibernate, Doctrine and Entity Framework. This implies builders with Java and Ruby backgrounds will really feel proper at dwelling.

TypeORM is an ORM that may run in Node.js, the browser, Cordova, PhoneGap, Ionic, React Native, NativeScript, Expo, and Electron platforms, and can be utilized with TypeScript and JavaScript. Its purpose is to all the time assist the most recent JavaScript options and supply further options that enable you to develop any form of utility that makes use of databases — from small purposes with just a few tables to large-scale enterprise purposes with a number of databases.

Putting in TypeORM requires putting in a number of packages, together with database adapters and extra TypeScript packages:

npm set up typeorm --save

npm set up reflect-metadata --save

npm set up @varieties/node --save-dev

npm set up mysql --save (you'll be able to set up mysql2 as an alternative as nicely)
npm set up pg --save
npm set up sqlite3 --save
npm set up mssql --save
npm set up sql.js --save

npm set up oracledb --save

npm i @sap/hana-client
npm i hdb-pool

npm set up mongodb --save

Subsequent, you’ll must allow the next settings in tsconfig.json:

"emitDecoratorMetadata": true,
"experimentalDecorators": true,

You might also must allow es6 within the lib part of compiler choices, or set up es6-shim from @varieties.

Alternatively, as an alternative of manually establishing a TypeORM undertaking, you’ll be able to merely use the TypeORM CLI device to scaffold the undertaking for you:

npm set up typeorm -g
typeorm init --name MyProject --database mysql

Fashions could be outlined utilizing the DataMapper implementation:

import {Entity, PrimaryGeneratedColumn, Column} from "typeorm";

export class Person {

    id: quantity;

    firstName: string;

    lastName: string;

    age: quantity;


const repository = connection.getRepository(Person);

const person = new Person();
person.firstName = "Timber";
person.lastName = "Noticed";
person.age = 25;

const allUsers = await;
const firstUser = await repository.findOne(1); 
const timber = await repository.findOne({ firstName: "Timber", lastName: "Noticed" });

await repository.take away(timber);

Alternatively, you should utilize an Lively Document sample to outline your fashions:

import {Entity, PrimaryGeneratedColumn, Column, BaseEntity} from "typeorm";

export class Person extends BaseEntity {

    id: quantity;

    firstName: string;

    lastName: string;

    age: quantity;


const person = new Person();
person.firstName = "Timber";
person.lastName = "Noticed";
person.age = 25;

const allUsers = await;
const firstUser = await Person.findOne(1);
const timber = await Person.findOne({ firstName: "Timber", lastName: "Noticed" });

await timber.take away();

TypeORM supplies a number of methods of constructing queries utilizing its personal Question Builder. Right here’s one in all its examples:

const firstUser = await connection
    .the place(" = :id", { id: 1 })

Beneath is the SQL output:

SELECT as userId,
    person.firstName as userFirstName,
    person.lastName as userLastName
FROM customers person

Right here’s an instance of a posh question:

const posts = await connection.getRepository(Submit)
    .the place(qb => {
        const subQuery = qb.subQuery()
            .from(Person, "person")
            .the place("person.registered = :registered")
        return "submit.title IN " + subQuery;
    .setParameter("registered", true)

Whereas TypeORM appears to cowl all of the options required to construct the information layer on your utility, there are just a few thorny points you need to be conscious of. Probably the most notable one is relating to efficiency, which has been reported and documented on this unresolved concern.

Because of the huge variety of options that the library helps, the backlog of unresolved points has piled as much as important ranges, inserting a heavy burden on the core maintainers. This concern has been addressed by the maintainers right here, the place they talk about the way forward for TypeORM.

Regardless, TypeORM is at the moment the most well-liked TypeScript ORM. This implies discovering builders acquainted with the library shall be simpler with regards to supporting your undertaking in the long term. Hopefully, extra contributors will be a part of the core upkeep group and assist stabilize the ORM.


  • Launch: Mar 11, 2018
  • Web site
  • GitHub: Utilized by 206
  • Slack
  • Databases : MongoDB, MySQL, MariaDB, PostgreSQL and SQLite

MikroORM is without doubt one of the youngest Node.js TypeScript ORM entrants on this listing. It helps each SQL and NoSQL databases, which is an incredible feat that not many ORMs have completed. It’s closely impressed by Doctrine and Nextras ORM. Anybody acquainted with these ought to really feel proper at dwelling with MikroORM.

The library is optimized for transactions and efficiency by way of Id Map patterns. It additionally helps the Knowledge Mapper sample. The documentation is great, with simple navigation to particular subjects. One of many key benefits with utilizing newer ORM libraries is that they’re designed to beat lots of the architectural points confronted by older and bigger libraries.

As you undergo the code samples I’ve supplied, you’ll discover the syntax is way easier to know. That is key for constructing large-scale initiatives that may stay maintainable in the long term. Let’s now undergo the set up course of:

npm i -s @mikro-orm/core @mikro-orm/mongodb     
npm i -s @mikro-orm/core @mikro-orm/mysql       
npm i -s @mikro-orm/core @mikro-orm/mariadb     
npm i -s @mikro-orm/core @mikro-orm/postgresql  
npm i -s @mikro-orm/core @mikro-orm/sqlite      

Subsequent, it is advisable to allow assist for decorators and esModuleInterop in tsconfig.json:

"experimentalDecorators": true,
"emitDecoratorMetadata": true,
"esModuleInterop": true,

Then name MikroORM.init as a part of bootstrapping your app:

const orm = await MikroORM.init({
  entities: [Author, Book, BookTag],
  dbName: 'my-db-name',
  kind: 'mongo', 
  clientUrl: '...', 

MikroORM supplies a command-line device, @mikro-orm/cli, which you entry utilizing npx or by putting in regionally and accessing it like this:

$ node node_modules/.bin/mikro-orm

$ npx mikro-orm

$ yarn mikro-orm

The command-line device helps with the event course of and may help you with performing duties similar to:

  • schema administration
  • importing SQL file to database
  • producing entities
  • database migration

MikroORM supplies 3 ways of defining entity courses. Right here’s one instance utilizing the replicate metadata syntax:

export class E book extends BaseEntity {

  title!: string;

  @ManyToOne(() => Creator)
  writer!: Creator;

  @ManyToOne(() => Writer, { wrappedReference: true, nullable: true })
  writer?: IdentifiedReference<Writer>;

  @ManyToMany({ entity: 'BookTag', fixedOrder: true })
  tags = new Assortment<BookTag>(this);


When you’ve outlined your entities, you should utilize the entity supervisor to persist and question your information:

const writer = new Creator('Jon Snow', '');
writer.born = new Date();

const writer = new Writer('7K writer');

const book1 = new E book('My Life on The Wall, half 1', writer);
book1.writer = writer;
const book2 = new E book('My Life on The Wall, half 2', writer);
book2.writer = writer;
const book3 = new E book('My Life on The Wall, half 3', writer);
book3.writer = writer;

await orm.em.persistAndFlush([book1, book2, book3]);

await orm.em.flush(); 

const guide = await orm.em.findOne(E book, 1);
guide.title = 'The way to persist issues...';

await orm.em.flush();

const books = await book, {});
for (const guide of books) {

Querying of entities could be executed by way of a situations object often known as FilterQuery. Listed below are totally different examples:

const customers = await, { firstName: 'John' });

const id = 1;
const customers = await, { group: id });

const ref = await orm.em.getReference(Group, id);
const customers = await, { group: ref });

const ent = await orm.em.findOne(Group, id);
const customers = await, { group: ent });

const customers = await, { $and: [{ id: { $nin: [3, 4] } }, { id: { $gt: 2 } }] });

const customers = await, [1, 2, 3, 4, 5]);

const user1 = await orm.em.findOne(Person, 1);

The library additionally helps:

  • fetching partial entities
  • fetching paginated outcomes
  • utilizing customized SQL fragments

To carry out much more complicated queries, you should utilize the Question Builder. Right here’s some instance code:

const qb = orm.em.createQueryBuilder(Creator);
qb.replace({ title: 'check 123', kind: PublisherType.GLOBAL }).the place({ id: 123, kind: PublisherType.LOCAL });



const res1 = await qb.execute();

Underneath the hood, MikroORM’s question builder makes use of Knex.js, which you may get entry to by way of the qb.getKnexQuery() operate. This implies all of the complicated and uncooked SQL queries you wish to assemble and run could be carried out. Therefore, you get the flexibleness and efficiency advantages of selecting MikroORM in your tech stack. The documentation on its Question Builder has many examples of question constructing — together with several types of joins — that are too many to listing right here. You’ll be happy to study that the Question Builder supplies a operate for displaying its SQL output throughout growth with out enabling a debug possibility. Right here’s an instance:

const qb = orm.em.createQueryBuilder(BookTag, 't');
qb.choose(['b.*', 't.*'])
  .leftJoin('t.books', 'b')
  .the place('b.title = ? or b.title = ?', ['test 123', 'lol 321'])
  .andWhere('1 = 1')
  .orWhere('1 = 2')
  .restrict(2, 1);


One concern of concern is that the library is kind of younger and the variety of customers are fairly low. Nonetheless, the library’s founder has enabled the GitHub sponsor function, which permits them to boost funds in order that they will work full-time on the undertaking. I consider this can be a higher strategy to open-source growth than having to work part-time on a distinct undertaking. By having full-time builders engaged on an open-source undertaking, they will give attention to sustaining the standard of the library and making certain the backlog is stored to a minimal. I do hope that they get a significant sponsor quickly.


  • Launch: April 2019
  • Web site
  • GitHub: Utilized by 5.7k
  • Databases : PostgreSQL, MySQL, SQLite, SQL Server

Prisma is the latest TypeScript ORM on this article. It describes itself as a “next-generation ORM” that makes working with databases simple for utility builders. It supplies the next instruments:

  • Prisma Shopper: a consumer library that gives type-safe entry to the database
  • Prisma Migrate (preview): a migration device that autogenerates once you make modifications to the schema file
  • Prisma Studio: a contemporary GUI for looking and managing information in your database

Prisma may be very totally different from all the opposite ORMs we’ve checked out. It doesn’t use object fashions (entity courses), however moderately a schema file to map all of the tables and columns. This file is utilized by the migration device to generate an SQL migration file and the consumer library to generate kind definitions. All generated kind definitions are saved in a .prisma/consumer/index.d.ts folder. Right here’s an instance of the generated illustration for Person kind:

export declare kind Person =  null

You could have observed that the posts reference within the mannequin isn’t current within the TypeScript definition. The really useful answer is to create a variation of the Person kind like this:

import { Prisma } from '@prisma/consumer'

kind UserWithPosts = Prisma.UserGetPayload<{
  embody: { posts: true }

Whenever you write a question, your code shall be checked to make sure you don’t reference a property that doesn’t exist and that you just assign the proper information kind for every property. Whenever you execute the question, all outcomes shall be returned in plain JavaScript objects.

Conventional ORMs present an object-oriented manner for working with relational databases by mapping tables to mannequin courses in your programming language. This strategy results in many issues which might be attributable to the object-relational impedance mismatch.

Establishing a Prisma undertaking is a little bit of a course of, which you will discover the complete directions right here. For now, we’re merely simply evaluating. Listed below are the essential set up steps:

npm set up prisma typescript ts-node @varieties/node --save-dev

You’ll must replace tsconfig.json as follows:

  "compilerOptions": {
    "sourceMap": true,
    "outDir": "dist",
    "strict": true,
    "lib": ["esnext"],
    "esModuleInterop": true

Begin by creating your utility’s information mannequin within the schema file situated at prisma/schema.prisma:

datasource db {
  supplier = "postgresql"
  url      = env("DATABASE_UR

mannequin Submit {
  id        Int      @default(autoincrement()) @id
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
  title     String   @db.VarChar(255)
  content material   String?
  printed Boolean  @default(false)
  writer    Person     @relation(fields: [authorId], references: [id])
  authorId  Int

mannequin Profile {
  id     Int     @default(autoincrement()) @id
  bio    String?
  person   Person    @relation(fields: [userId], references: [id])
  userId Int     @distinctive

mannequin Person {
  id      Int      @default(autoincrement()) @id
  e mail   String   @distinctive
  title    String?
  posts   Submit[]
  profile Profile?

Subsequent, you’ll must map your information mannequin to the database schema utilizing prisma migrate CLI device:

npx prisma migrate dev --name init --preview-feature

We’ll skip forward the set up course of and take a look at our setup code in index.ts:

import { PrismaClient } from '@prisma/consumer'

const prisma = new PrismaClient()

async operate most important() {
  const allUsers = await prisma.person.findMany()

most important()
  .catch(e => {
    throw e
  .lastly(async () => {
    await prisma.$disconnect()

Beneath is a pattern demonstrating the way to persist information and question data:

async operate most important() {
  await prisma.person.create({
    information: {
      title: 'Alice',
      e mail: '',
      posts: {
        create: { title: 'Howdy World' },
      profile: {
        create: { bio: 'I like turtles' },

  const allUsers = await prisma.person.findMany({
    embody: {
      posts: true,
      profile: true,
  console.dir(allUsers, { depth: null })

Whenever you run the above code, the outcomes shall be returned as JavaScript objects like this:

    email: '',
    id: 1,
    name: 'Alice',
    posts: [
        content: null,
        createdAt: 2020-03-21T16:45:01.246Z,
        id: 1,
        published: false,
        title: 'Hello World',
        authorId: 1,
    profile: {
      bio: 'I like turtles',
      id: 1,
      userId: 1,

Prisma’s documentation seems to be fairly, and it seems to have plenty of content material. Sadly, I’ve discovered it troublesome discovering the knowledge you want. Both it’s because of an over-complicated navigation system, or that particular content material is lacking. Data is unfold over a number of sections, together with:

  • ideas
  • guides
  • reference
  • assist/assist articles

Prisma is a more moderen library that follows a distinct philosophy on information layer constructing. It additionally seems to be rising quicker than MikroORM, particularly because it was launched a yr later.


As we conclude, I’d wish to briefly talk about the case towards utilizing ORM libraries in your undertaking. The principle arguments embody:

  • cumbersome, inefficient queries
  • frustrations utilizing a library
  • migration points: protecting entity courses and the database scheme in sync
  • lack of kind security when utilizing the uncooked SQL possibility

You possibly can learn all of the arguments towards utilizing ORM libraries right here and right here.

Having checked out all present JavaScript and TypeScript ORM libraries, you need to be conscious that every one differs in its implementation. Many of the arguments towards ORM libraries have been resolved by the newer ones, similar to Object.js and Prisma. For those who determine to not use an ORM library, you’ll need to determine the person instruments and libraries that make up your information layer stack.

The best way I see it, selecting an ORM on your undertaking is the very best answer due to this one purpose: documentation.

As builders, we’re fairly unhealthy at documenting our personal code. If we had been to implement a customized answer, or implement a library that’s not well-known, future maintainers would have a tough time protecting your utility updated with its enterprise wants.

Nonetheless, when you use a well-documented ORM library, it turns into a lot simpler for them to work in your utility lengthy after you’ve left the undertaking. It is because ORMs instill good code practices, similar to structure and patterns similar to Knowledge Mapper. And whereas which will introduce a studying curve, it’s higher in the long term.

I hope I’ve supplied helpful data that may enable you consider an ORM library on your undertaking. For those who’d like a advice, select a TypeScript ORM library that’s is most suited to an enterprise-class undertaking.

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