javascript - typeorm trying to delete relation table data when there is no change - Stack Overflow

I have project entity which has systemInstances. And systemInstance have a manytomany child and parent relation. When I try to update Project entity with same systemInstances, typeorm giving this error

 ERROR [ProjectController] Failed to update project version in project.service.ts: QueryFailedError: update or delete on table "system_instance" violates foreign key constraint "FK_3108b2b6c17bb0ed49ad71b131c" on table "system_instance_relationship"

as far as I understand typeorm trying to delete relation data from system_instance_relation table but Im not changing anything inside of the systemInstance, actually Im just passing the same object to save method.

when I save Project into db, systemInstances should be also updated with relations.

Here is my code

  async updateDraftVersion(toUpdate: UpdateProjectDto, user: User) {
    try {
          const id = toUpdate.id;
          const project = await this.projectRepository.findOne({
            where: {
              id: id,
            },
            relations: [
              'createdBy',
              'createdBy.userRole',
              'systemInstances',
              'systemInstances.parent',
              'systemInstances.children',
              'systemInstances.createdBy',
              'systemInstances.createdBy.userRole',
              'systemInstances.systemTemplate',
              'systemInstances.systemTemplate.systemCategory',
              'systemInstances.softwarePackages',
            ],
          });
          if (!project) {
            throw new APIError(
              HttpStatus.NOT_FOUND,
              `Can not found project with Id: ${id}`,
            );
          }

          project.name = toUpdate.name;
          project.description = toUpdate.description; 
          project.yardNumber = toUpdate.yardNumber;

          const updatedItem = await this.projectRepository.save(project);
          

          return updatedItem;
    } catch (e) {
      if (e instanceof APIError) {
        throw e;
      } else {
        throw new APIError(
          HttpStatus.INTERNAL_SERVER_ERROR,
          `Failed to update project version in project.service.ts: ${e}`,
        );
      }
    }
  }

here is my Project Entity

@Entity()
export class Project extends BaseEntity {
  @Column({ type: 'text', nullable: false })
  yardNumber: string;

  @Column({ type: 'text', nullable: false })
  name: string;

  @Column({ type: 'text', nullable: false })
  description: string;

  @Column({ type: 'text', default: VersionStatus.DRAFT, nullable: false })
  status: string;

  @Column({ type: 'numeric', default: 1, nullable: false })
  version: number;

  @OneToMany(() => SystemInstance, (system) => system.project, { cascade: true, onDelete:'CASCADE', onUpdate:'CASCADE' })
  systemInstances: SystemInstance[];
}

and system.instance.entity

@Entity()
export class SystemInstance extends BaseEntity {
  @Column({ type: 'text', nullable: false })
  systemId: string;

  @Column({ type: 'text', nullable: false })
  name: string;

  @Column({ type: 'text', nullable: false })
  description: string;

  @ManyToOne(() => SystemTemplate, (systemTemplate) => systemTemplate.systems)
  systemTemplate: SystemTemplate;

  @ManyToOne(() => Project, (project) => project.systemInstances,
   { orphanedRowAction: 'delete' }
  )
  project: Project;

  @ManyToMany(() => SystemInstance, (system) => system.children)
  @JoinTable({
    name: 'system_instance_relationship',
    joinColumn: { name: 'child_id', referencedColumnName: 'id' },
    inverseJoinColumn: { name: 'parent_id', referencedColumnName: 'id' },
  })
  parent: SystemInstance;

  @ManyToMany(() => SystemInstance, (system) => system.parent, { cascade: true, orphanedRowAction: 'delete' })
  @JoinTable({
    name: 'system_instance_relationship',
    joinColumn: { name: 'parent_id', referencedColumnName: 'id' },
    inverseJoinColumn: { name: 'child_id', referencedColumnName: 'id' },
  })
  children: SystemInstance[];

  @ManyToMany(
    () => SoftwarePackage,
    (softwarePackage) => softwarePackage.systemTemplates,
  )
  @JoinTable({
    name: 'system_instance_software_package',
    joinColumn: { name: 'system_instance_id', referencedColumnName: 'id' },
    inverseJoinColumn: {
      name: 'software_package_id',
      referencedColumnName: 'id',
    },
  })
  softwarePackages: SoftwarePackage[];
}