需要为关系定义外键或者需要实现 Valuer/Scanner 接口答案

【问题标题】：need to define a foreign key for relations or it need to implement the Valuer/Scanner interface需要为关系定义外键或者需要实现 Valuer/Scanner 接口
【发布时间】：2020-12-15 19:51:07
【问题描述】：

如何解决这个问题？我遇到了这样的错误

struct gomar/campaign.Campaign 的字段 User 发现无效字段，需要为关系定义外键或者需要实现 Valuer/Scanner 接口

package campaign

import (
    "gomar/user"
    "time"
)

type Campaign struct {
    ID               int
    userID           int
    Name             string
    ShortDescription string
    Description      string
    Slug             string
    CreatedAt        time.Time
    UpdatedAt        time.Time
    CampaignImages   []CampaignImage
    User             user.User
}

type CampaignImage struct {
    ID         int
    CampaignID int
    FileName   string
    IsPrimary  int
    CreatedAt  time.Time
    UpdatedAt  time.Time
}

【问题讨论】：

标签： go go-gorm

【解决方案1】：

需要根据official doc! 为 user.User 添加标签。

type Campaign struct {
    ID               int
    userID           int
    Name             string
    ShortDescription string
    Description      string
    Slug             string
    CreatedAt        time.Time
    UpdatedAt        time.Time
    CampaignImages   []CampaignImage
    User             user.User  `gorm:"foreignKey:Uid"`
}

type CampaignImage struct {
    ID         int
    CampaignID int
    FileName   string
    IsPrimary  int
    CreatedAt  time.Time
    UpdatedAt  time.Time
}

请同时为 user.User 执行迁移

err := DB.AutoMigrate(&user.User{})
if err != nil {
  panic("migration failed")
}

【讨论】：