Postgresql Has-Many 关系插入相同的 id 错误

Question

我有 2 个结构有很多这样的关系：type Domain struct {    ID     uint    `gorm:"primaryKey;type:serial"`    Emails []Email `gorm:"foreignKey:ID" "column:emails"`}type Email struct {    ID      uint   `gorm:"primaryKey;type:serial"`    Address string `gorm:"column:address"`}我在这里关注 gorm 文档：https ://gorm.io/docs/associations.html#Association-Mode据我了解，当我们插入一条Domain记录时，gorm首先将数组电子邮件（[]Email）插入数据库，我在尝试插入数据库时遇到了这样的问题：var domain models.Domainvar emails []models.Emailfor key, _ := range Output {  emails = append(emails, models.Email{Address: key})}domain = models.Domain{  Emails: emails,}dataAccess.Domain.Insert(domain) // db.Create(&domain)这是我的控制台中的输出：2020/09/10 10:37:46 /Users/tho/go/src/txxxx/exxxx/dataAccess/domains.go:18 ERROR: ON CONFLICT DO UPDATE command cannot affect row a second time (SQLSTATE 21000)[362.162ms] [rows:0] INSERT INTO "emails" ("address","id") VALUES ('[e-mail]',2),('[e-mail]',2) ON CONFLICT ("id") DO UPDATE SET "id"="excluded"."id" RETURNING "id"2020/09/10 10:37:46 /Users/tho/go/src/txxxx/exxxx/dataAccess/domains.go:18 ERROR: ON CONFLICT DO UPDATE command cannot affect row a second time (SQLSTATE 21000)[1078.499ms] [rows:1] INSERT INTO "domains" DEFAULT VALUES RETURNING "id"ERRO[0050] Err: ERROR: ON CONFLICT DO UPDATE command cannot affect row a second time (SQLSTATE 21000) Gorm 插入 2 封具有相同 id 的电子邮件，因此 postresql 错误如上所示。我怎样才能避免相同的 id，因为它primaryKey已经serial存在（自动增量）。

Answer 1

你需要改变

Emails []Email `gorm:"foreignKey:ID" "column:emails"`

至

Emails []Email `gorm:"foreignKey:DomainId" "column:domain_id"`

并添加

DomainId uint   `gorm:"column:domain_id"`

在type Email struct

尝试：

type Domain struct {

    ID     uint    `gorm:"primaryKey;type:serial"`

    Domain string  `gorm:"column:domain"`

    Emails []Email `gorm:"foreignKey:DomainId" "column:domain_id"`

}

type Email struct {

    ID       uint   `gorm:"primaryKey;type:serial"`

    Address  string `gorm:"column:address"`

    DomainId uint   `gorm:"column:domain_id"`

}