我如何执行嵌套删除 gorm Golang？

Question

我有 table 位有汽车的客户，而汽车有服务。当我删除汽车时，我还想从数据库中删除服务当我删除客户时，我希望能够删除客户及其汽车和服务。

我尝试了以下方法来删除与汽车相关的汽车和服务，但它只从数据库中删除了汽车，我该如何同时删除汽车及其服务？

type Customer struct {
    gorm.Model

    FirstName string
    LastName  string
    Phone     string `gorm:"typevarchar(100);unique_index"`
    Cars      []Car  `gorm:"constraint:OnDelete:CASCADE;"`
}

type Car struct {
    gorm.Model

    Make       string
    Modelo     string
    Color      string
    VinNumber  string     `gorm:"typevarchar(100);unique_index"`
    Services   []*Service `gorm:"constraint:OnDelete:CASCADE;"`
    CustomerId int
}

type Service struct {
    gorm.Model

    Comment string
    Miles   string
    CarId   int
}

//endpoints
//delete customer
func deleteCustomer(w http.ResponseWriter, r *http.Request) {
    params := mux.Vars(r)

    setupResponse(&w, r)
    if (*r).Method == "OPTIONS" {
        return
    }

    var customer Customer
    db.First(&customer, params["id"])
    db.Unscoped().Delete(&customer)

    json.NewEncoder(w).Encode(&customer)
}

func deleteCar(w http.ResponseWriter, r *http.Request) {
    setupResponse(&w, r)
    if (*r).Method == "OPTIONS" {
        return
    }

    params := mux.Vars(r)

    var car Car
    db.First(&car, params["id"])
    db.Select("Services").Unscoped().Delete(&car)
    json.NewEncoder(w).Encode(&car)
}

我已经尝试了我在 Whosebug 和文档中看到的大部分内容，但到目前为止似乎没有任何效果。

Answer 1

阅读文档和一堆 Whosebug 答案后，对我来说没有任何用处。文档 and/or Whosebug 建议我在迁移模型时添加约束，or/and 将约束添加到结构 gorm:"constraint:OnDelete:CASCADE;" ，我也试过 db.Select("cars").Delete(&customers) 但没有成功。这就是我的处理方式，不确定这是否是最佳做法，但它会从数据库中删除其相关记录。我像这样更新了 deleteCustomer 和 deleteCar 端点：

//delete customer
func deleteCustomer(w http.ResponseWriter, r *http.Request) {
    params := mux.Vars(r)

    setupResponse(&w, r)
    if (*r).Method == "OPTIONS" {
        return
    }

    var customer Customer
    var cars []Car

    db.First(&customer, params["id"])
    db.Model(&customer).Related(&cars)

    deleteServicesSqlStatement := `
        DELETE FROM services
        WHERE car_id = ;`

    for i, car := range cars {
        fmt.Println(i, car.ID)
        err := db.Exec(deleteServicesSqlStatement, car.ID).Error
        if err != nil {
            fmt.Println(err)
        }

    }

    DeleteCarsSqlStatement := `
        DELETE FROM cars
        WHERE customer_id = ;`

    err := db.Exec(DeleteCarsSqlStatement, params["id"]).Error
    if err != nil {
        fmt.Println(err)
    }

    db.Debug().Unscoped().Delete(&customer)
    json.NewEncoder(w).Encode(&customer)

}


//delete car
func deleteCar(w http.ResponseWriter, r *http.Request) {
    //handle CORS
    setupResponse(&w, r)
    if (*r).Method == "OPTIONS" {
        return
    }

    params := mux.Vars(r)

    var car Car
    db.First(&car, params["id"])

    sqlStatement := `
        DELETE FROM services
        WHERE car_id = ;`

    err := db.Exec(sqlStatement, params["id"]).Error

    if err != nil {
        fmt.Println(err)
    }

    db.Debug().Unscoped().Delete(&car)
    json.NewEncoder(w).Encode(&car)
}

我如何执行嵌套删除 gorm Golang？

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