Why NestJs saves model with 'null' relation, if it is required in Entity and DTO?

Question

I have an Entities:

Company:

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

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

  @Column()
  name: string;
}

Unit:

import { Company } from '../../companies/entities/company.entity';
import { Entity, PrimaryGeneratedColumn, Column, ManyToOne } from 'typeorm';

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

  @Column()
  name: string;

  @Column()
  address: string;

  @ManyToOne((type) => Company)
  company: Company;
}

And DTOs for them:

export class CompanyCreateDto {
    name: string
}

export class UnitCreateDto {
    name: string
    address: string
    company: { id: number }
}

This request works fine, and creates a relation.

POST http://localhost:3000/api/units
content-type: application/json

{ 
    "name": "Unit name 12", 
    "address": "city, street, house, office 234", 
    "company": {"id": 1}
 }

If I remove "name" or "address", I get an error (which is fine): ERROR [ExceptionsHandler] null value in column "name" of relation "unit" violates not-null constraint But if I remove "company" from request, the entity will be saved with company: null.

I can't understand why is that?