如何更改默认学说实体方案

默认的一对一关系方案为

CREATE TABLE Product (
    id INT AUTO_INCREMENT NOT NULL,
    shipping_id INT DEFAULT NULL,
    PRIMARY KEY(id)
) ENGINE = InnoDB;
CREATE TABLE Shipping (
    id INT AUTO_INCREMENT NOT NULL,
    PRIMARY KEY(id)
) ENGINE = InnoDB;
ALTER TABLE Product ADD FOREIGN KEY (shipping_id) REFERENCES Shipping(id);

但我需要使用这个方案，但要做一些修改ON DELETE SET NULL ON UPDATE SET NULL;:

CREATE TABLE Product (
    id INT AUTO_INCREMENT NOT NULL,
    shipping_id INT DEFAULT NULL,
    PRIMARY KEY(id)
) ENGINE = InnoDB;
CREATE TABLE Shipping (
    id INT AUTO_INCREMENT NOT NULL,
    PRIMARY KEY(id)
) ENGINE = InnoDB;
ALTER TABLE Product ADD FOREIGN KEY (shipping_id) REFERENCES Shipping(id) ON DELETE SET NULL ON UPDATE SET NULL;

我可以用学说实体配置创建这个方案吗?

注:I有两个实体:Vendor和Image

BW'ShopBundle'Entity'Vendor:
    type: entity
    table: vendors
    id:
        id:
            type: integer
            id: true
            generator:
                strategy: AUTO
    oneToOne:
        image:
            targetEntity: BW'FileBundle'Entity'Image
            cascade: [persist, remove]

和

BW'FileBundle'Entity'Image:
    type: entity
    table: images
    id:
        id:
            type: integer
            id: true
            generator:
                strategy: AUTO
    fields:
        filename:
            type: string
            length: 255
            nullable: true

我使用oneToOne Unidirectional关系。

所以当我删除Image对象时，我有一个错误，因为我有Unidirectional关系(重要的是要知道我不能将关系更改为bidirectional)