Node.js - TypeORM support

Introduction

This section describes support for the Node.js TypeORM framework.

Connection

TypeORM can be used both with SQL and NoSQL databases. The database type is set through the connection option type:

import {createConnection, Connection} from "typeorm";

const connection = await createConnection({
    type: "mysql",
    host: "localhost",
    port: 3306,
    username: "test",
    password: "test",
    database: "test"
});

The only NoSQL database which is supported by TypeORM is MongoDB. A connection object is created by our analyzer only for MongoDB databases. The name of the connection is the URL mongodb://localhost/test which is constructed using the host and database values. An Entity is a class that maps to a database table (or collection when using MongoDB):

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

@Entity()
export class User {

    @PrimaryGeneratedColumn()
    id: number;

    @Column()
    firstName: string;

    @Column()
    lastName: string;

    @Column()
    isActive: boolean;

}

When a MongoDB database is used, for each entity, the extension creates a MongoDB collection object. A parentLink between that collection and the corresponding connection is added. For an SQL connection, the entity will be associated with the SQL table having the same name (if that table exists).

Link to table/collection

TypeORM provide several ways to access and/or update a table or collection. One can use an entity manager, a repository, or a query builder. The use of InjectRepository from @nestjs/typeorm is also supported. Here is an example with a repository:

import {getRepository} from "typeorm";
import {User} from "./user";

function update_user(){
    const userRepository = getRepository(User); 
    const user = await userRepository.findOne(1);
    user.name = "fooname";
    await userRepository.save(user);
}

• The userRepository.findOne(1) method call generates a “useSelectLink” to the User table/entity.
• The userRepository.save(user) method call  generates a “useUpdateLink” to the User table/entity.

Example for a mongodb database: both useSelect and useUpdate links are created between the update_user function and the User entity which belongs to the <Default> connection:

Example for a SQL database: both useSelect and useUpdate links are created between the update_user function and the user table. 

Cascades

In the following example, the User entity has its column profile with a one-to-one relation with the Profile entity and cascade set to true:

import {Entity, PrimaryGeneratedColumn, Column, OneToOne, JoinColumn} from "typeorm";
import {Profile} from "./profile";

@Entity()
export class User {

    @PrimaryGeneratedColumn()
    id: number;

    @Column()
    name: string;

    @OneToOne(type => Profile, {
        cascade: true
    })
    @JoinColumn()
    profile: Profile;

}

When the profile column of a user instance is saved, if the profile column of that instance was updated with a profile instance, that profile instance is also saved.

import {getRepository} from "typeorm";
import {User} from "../entity_dir/user";
import {Profile} from "../entity_dir/profile";


function update_user(){
    const userRepository = getRepository(User); 
    const user = await userRepository.findOne(1);
    const profile = new Profile()
    user.name = "fooname";
    user.profile = profile
    await userRepository.save(user);
}

In the previous example, a useUpdate link is created between the update_user function and both the user and profile tables/entities:

SQL queries

Plain SQL queries can also be carried out using TypeORM such as with the following code:

import {getConnection} from "typeorm";

export class A {
    public foo() {
        const manager = getConnection().manager;
        const rawData = await manager.query(`SELECT * FROM USER`);
    }
} 

In this example, a TypeScript query object is created and a callLink between the foo method and that query is added. The SQL Analyzer can then link that query with the corresponding table:

Known limitations

The following features are not supported

• use of ormconfigs.yml, ormconfigs.env and ormconfigs.xm ORM configuration files 
• custom repositories
• view entities
• entity listeners and subscribers
• connectionManager