kunxin-chor / nestjs-ecommerce

TypeORM and MVC demonstration

Dependencies

npm install --save @nestjs/typeorm typeorm mysql
npm install --save rxjs

Add the TypeORM module to the app module

In app.modue.ts

1. Import the module

   import { TypeOrmModule } from '@nestjs/typeorm';
   

2. Add TypeOrmModule to the imports array:

    @Module({
        imports: [ TypeOrmModule.forRoot({
            type: 'mysql',
            host: 'localhost',
            port: 3306,
            username: 'root',
            password: 'root',
            database: 'test',
            entities: [],
            synchronize: true,
            })],
        controllers: [AppController, BooksController],
        providers: [AppService],
    })
    export class AppModule {}
   

3. Configure the host, username, database and password.

4. If there are problem authenticating due to the error:

    Client does not support authentication protocol requested by server; consider upgrading MySQL client
   

   Then perform the following steps inside the MySQL client:

   ALTER USER 'gitpod'@'%' IDENTIFIED WITH mysql_native_password BY '';
   FLUSH PRIVILEGES;
   

Create an entitiy

An entity represents a table in the database.

Create and add the following file to \src folder. Save as book.entity.ts

/* A Book Entity */


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

@Entity()
export class Book {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  title: string;

  @Column()
  author: string;

  @Column()
  pageCount: number;

  @Column({ default: true })
  isAvailable: boolean;
}

After which, refer to it in your app.module.ts

{
      type: 'mysql',
      host: 'localhost',
      port: 3306,
      username: 'gitpod',
      password: '',
      database: 'test',
      entities: [Book],
      synchronize: true,
}

Inside the `app.module.ts` file,  add in ` TypeOrmModule.forFeature([Book])` into the `imports` array. This will allows
every controller in the `app.module.ts` to access the Book entity.

Now if we restart the NestJS app with nest start, the new table for the Book entity will be created.

Inject the Repo

TypeORM provide a repository for each entity. It allows us to execute read, insert, update, delete and etc.

Before we can use the repository in our controller, we have to inject into our controller first:

  constructor(  
        @InjectRepository(Book)
        private booksRepository: Repository<Book>) {
    }

Doing a READ:

Now we want to be able to access this entity in our BooksController.

Add the following to the BooksController:

 @Get()
    async getBooks() {
        let results = await this.booksRepository.find();
        return {
            books: results
        }
    }