Gorm Associations BeforeCreate 回调未按预期工作

Question

我有 Customer 结构

type Customer struct {
    Model
    Email                 string     `json:"email,omitempty"`
    Addresses             []Address
}

func (c *Customer) BeforeCreate() (err error) {
    if err := c.GenerateID(); err != nil {
        return err
    }
    return c.Marshal()
}

和地址结构

type Address struct {
    Model
    CustomerID         string
    Address1           string
}

func (a *Address) BeforeCreate() error {
// The ID is still generated, but the insert query has no `id` in it
    if err := a.GenerateID(); err != nil {
        return err
    }
    return nil
}

模型结构

type Model struct {
    ID        string `gorm:"primary_key;type:varchar(100)"`
    CreatedAt time.Time
    UpdatedAt time.Time
    DeletedAt *time.Time `sql:"index"`
}

func (model *Model) GenerateID() error {
    uv4, err := uuid.NewV4()
    if err != nil {
        return err
    }
    model.ID = uv4.String()
    return nil
}

一个客户:

customer := &model.Customer{
    Email:     "a",
    Addresses: []model.Address{
        {
            Address1: "abc street",
        },
    },
}


if err := gormDb.Create(customer).Error; err != nil {
    return nil, err
}

我收到一个错误:错误 1364:字段“id”没有地址对象的默认值

但是，如果我删除 Address 关联，一切正常。并生成客户的 Id。

    customer := & model.Customer{
    Email:     "a",
    //Addresses: []model.Address{
        //{
            //Address1: "abc street",
        //},
    //},
}

如何保持 Address 关联并成功插入两者，并且仍然使用此 ID 生成机制？

Answer 1

您可以使用 scope.SetColumn 在 BeforeCreate Hook 中设置字段的值

func (a *Address) BeforeCreate(scope *gorm.Scope) error {
  scope.SetColumn("ID", uuid.New())
  return nil
}

引用:https://v1.gorm.io/docs/create.html#Setting-Field-Values-In-Hooks