我想預(yù)加載與gorm的關(guān)系，它沒有用函數(shù)填充切片。M2MPreload這是 sql 架構(gòu)create table project ( id int generated by default as identity, name varchar(64) not null, slug varchar(64) not null, image_url text, constraint project_pk primary key (id), constraint project_unq unique (name, slug));create table donation ( id int generated by default as identity, user_id varchar(36) not null, total_amount numeric(7, 2) not null, currency varchar(3) not null, constraint donation_pk primary key (id));create table donation_detail ( donation_id int not null, project_id int not null, amount numeric(7, 2) not null, primary key (donation_id, project_id));這些是我的血腥模型type Donation struct { ID uint64 `json:"id" gorm:"primarykey"` UserID string `json:"user_id"` PaypalOrderID string `json:"paypal_order_id"` TotalAmount float64 `json:"total_amount"` Currency string `json:"currency"` DonationDetails []*DonationDetail `json:"donation_details" gorm:"many2many:donation_detail;"`}type Project struct { ID uint64 `json:"id" gorm:"primarykey"` Name string `json:"name"` Slug string `json:"slug"` ImageURL string `json:"image_url"`}type DonationDetail struct { DonationID uint64 `json:"donation_id" gorm:"primaryKey"` ProjectID uint64 `json:"project_id" gorm:"primaryKey"` Amount float64 `json:"amount"` Project Project}我想退還捐款，它的詳細(xì)信息包括項目信息。像這樣：{ "id": 1, "user_id": "e14a98d1-0c4a-45c3-b748-5ac6ba733b99", "paypal_order_id": "6SR91505YA360210R", "total_amount": 10000, "currency": "EUR", "donation_details": [ { "donation_id": 1, "project_id": 1, "amount": 3000, "project": { "project_id": 1, "name": "First Project", "slug": "first_project", "image_url": "img1.jpg" } },
1 回答
阿波羅的戰(zhàn)車
TA貢獻1862條經(jīng)驗 獲得超6個贊
有幾件事需要嘗試和修復(fù)：
您可能不需要該屬性來加載切片，因為它們只能使用 加載。如果您有外鍵，可以按如下方式添加它：many2manyDonationDetailDonationID
type Donation struct {
ID uint64 `json:"id" gorm:"primarykey"`
UserID string `json:"user_id"`
PaypalOrderID string `json:"paypal_order_id"`
TotalAmount float64 `json:"total_amount"`
Currency string `json:"currency"`
DonationDetails []*DonationDetail `json:"donation_details" gorm:"foreignKey:DonationID"`
}
您不需要該方法，因為已經(jīng)是一個指針。但是，要加載數(shù)據(jù)，您還需要預(yù)加載。&dFirstdProject
func List(donationID string) (*Donation, error) {
var d *Donation
if err := db.Debug().Preload("DonationDetails.Project").First(d, donationID).Error; err != nil {
return nil, fmt.Errorf("could not list donation details: %w", err)
}
return d, nil
}
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