Gain insights into Node.js, Express, and TypeScript advantages. Learn Docker setup for PostgreSQL, discover Prisma and TypeORM, and explore advanced ORM features via hands-on projects.

ORM-libraries-for-NodeJS-Typescript-and-SQL.png

ORM.tar.gz

node-server

typeorm-setup

docker-prisma

basic-api

basic-express

typeorm-crud

typeorm-SQL

typeorm-associations

Object Relational Mappers (ORM) are becoming popular in building modern backend applications as they help maintain a consistent codebase, improve security, and provide ease in working with different databases. Also, TypeScript has almost become a must-use language for building JavaScript applications.

In this course, you’ll start by getting familiar with Node.js and Express. You’ll then go over the main features of TypeScript and its advantages over JavaScript. Next, you’ll learn how to do a Docker setup of PostgreSQL. Moreover, this will be followed by introductions to two of the most popular TypeScript ORMs for Node.js: Prisma and TypeORM. Along the way, you’ll practice your skills by building two projects. In the end, you’ll explore some advanced features of these ORMs.

This course will equip you with the skills, knowledge, and hands-on experience to work with SQL databases and Node.js using TypeScript ORMs.

Getting Started with TypeScript ORM Libraries for Node.js

# Overview

In this lesson, we’ll look at CRUD operations. We’ll be using NestJS as the API library. It includes three basic files:

  * `app.controller.ts`: This file handles all the routes, for example,`/get/employees`.
* `app.service.ts`: This file has the algorithms and implementations that connect with databases and third-party APIs.
* `app.module.ts`: This module registers other modules (for example, entities) that are used in the `app.service.ts` or `app.controller.ts` files.








# Migration

Whenever we update or add an entity, it’s essential to run a migration. A migration updates the SQL table to fit the entity or the model.

Open `package.json`, and add two more scripts to generate and run a migration, as shown below:
 



"scripts": {
    "migrate:generate": "./node_modules/.bin/ts-node ./node_modules/.bin/typeorm migration:generate -d data-source.ts ./src/migrations/$npm_config_name",
    "migrate:revert": "./node_modules/.bin/ts-node ./node_modules/.bin/typeorm migration:revert -d data-source.ts",
    "migrate:run": "./node_modules/.bin/ts-node ./node_modules/.bin/typeorm migration:run -d data-source.ts"
  }

Next, at the root directory, create a `data-source.ts` file. This file defines the database configurations and related information. Update the file with the code below:
 

import { DataSource } from "typeorm";

export const AppDataSource = new DataSource({
    type: "postgres",
    host: "localhost",
    port: 5432,
    username: "postgres",
    password: "password",
    database: "company_db",
    synchronize: false,
    logging: true,
    entities: ["src/entities/**/*.ts"],
    migrations: ["src/*-migrations.ts"],
})

The latest versions of TypeORM (0.3.10 and newer) use the `Datasource` object to define the database connection settings and related information. Previous versions used the `ormconfig.json` files. The `DataSource` object file specifies the path of our `entities` and `migrations` files (lines 12 and 13), database `type`, `username`, and `password`.

To run a migration, we use the command below:

- `migrate:generate`: This script generates the migration files, which represent code snippets of SQL queries.
- `migrate:run`: This command executes the code’s SQL queries generated in the files.
Open the terminal on the root directory, and run the migration script:


Learn how to perform basic CRUD operations using NestJS as the API library.


CRUD Operations with TypeORM

Learn how to perform basic CRUD operations using NestJS as the API library.

Course Overview

Node.js Features and Setup

TypeScript Features and Setup

SQL – Introduction and Setup

Understanding ORMs for Node.js

Prisma

Flight Booking System

TypeORM

Advanced Topics

School Grading System

Conclusion

CRUD Operations with TypeORM

Overview

Migration