建立Role Entity

@Entity()
export class Role {
    @PrimaryGeneratedColumn()
    id: number;
    @Column({
        length: 50,
    roleName: string;
    @ManyToMany(type => User, user => user.roles) //設定bi-directional關聯
    users: User[];
新增RoleDTO
import { IsString, MaxLength } from "class-validator";
export class RoleDTO {
    @IsString()
    @MaxLength(100)
    roleName: string;
新增RoleService，記得註冊到Module
@Injectable()
export class RolesService {
    constructor(
        @InjectRepository(Role) // 注入 typeorm repository
        private readonly roleRepo: Repository<Role>,
    async addRole(roleDto: RoleDTO){
        const role = new Role();
        role.roleName = roleDto.roleName;
        return await this.roleRepo.save(role);
    async getRoleById(id){
        return await this.roleRepo.findOne(id);
    async getRolesByIds(ids){ //用在新增使用者時候要回傳Role[]
        return await this.roleRepo.findByIds(ids);
    async getRoles(){
        return await this.roleRepo.find({relations:['users']}); //載入關聯屬性
修改appcontroller
  @Get('role/list')
  getRoles(){
    return this.roleService.getRoles();
  @Get('role/:roleId')
  getRoleById(@Param('roleId') id){
    return this.roleService.getRoleById(id);
  @Post('role')
  @UsePipes(new ValidationPipe({transform:true}))
  addRole(@Body() roleDTO: RoleDTO){
    return this.roleService.addRole(roleDTO);
修改user.entitie.ts，新增多對多關聯屬性
    @ManyToOne(type => Department, dep => dep.users)
    dep: Department;
    @RelationId((user: User) => user.dep)
    depId: number;
    @ManyToMany(type => Role, role => role.users) //建立bi-directional多對多
    @JoinTable() // 告訴typeorm要建立join table
    roles: Role[];
修改userDTO，加入roleIds屬性
    @IsNumber()
    depId: number;
    @IsNumber({ 
        allowNaN: false,
        allowInfinity:false,
    },{each:true //檢查陣列每一個元素是否都是數字})
    roleIds: number[];
修改user.service.ts
      async addUser(data: UserDTO): Promise<User>{
        const user = new User();
        user.username = data.username;
        user.email = data.email;
        //user.depId  = data.depId; 不能只指定id，必須傳入物件
        user.dep = await this.depService.getDepById(data.depId);
        // 先要取得role物件陣列，再指給user物件下的roles，save時才會儲存關聯
        user.roles = await this.roleService.getRolesByIds(data.roleIds);
        return await this.userRepo.save(user); // 新增一筆user資料
      async getUsers(): Promise<User[]>{
        return await this.userRepo.find({relations: ['dep', 'roles']}); // 載入dep及roles導覽屬性
      async getUserById(id): Promise<User>{
        return await this.userRepo.findOne(id, {relations: ['dep', 'roles']}); // 載入dep及roles導覽屬性
        // return await this.userRepo.findOneOrFail(id); // 以id搜尋，沒找到會丟出例外
      async updateUser(id, data: UserDTO){
        const user = new User();
        user.username = data.username;
        user.email = data.email;
        user.dep = await this.depService.getDepById(data.depId);
        user.roles = await this.roleService.getRolesByIds(data.roleIds);
        return await this.userRepo.update(id, user); // 用data裡的值更新到資料庫
使用postman測試

我已預先建立三個Role，先測試新增使用者

列出使用者清單，看是否有儲存關聯資料

列出Role清單，看是否載入關聯資料

Github source code