英文:
GORM unable to update data in one to many relationship
问题
我有两个表，用户（users）和文档（documents）。它们之间的关系是每个文档必须属于一个用户，使用一对多的关系。当我尝试更新一个文档时，出现以下错误：
> 错误：插入或更新表“documents”违反了外键约束“fk_users_documents”（SQLSTATE 23503）
这是我的结构定义和更新函数：
type User struct {
gorm.Model
Name string
Email string
Password string
Documents []Document
}
type Document struct {
gorm.Model
Name string
UserID uint
}
// 根据ID更新文档
func (h handler) UpdateDocument(w http.ResponseWriter, r *http.Request) {
// 首先，我们需要解析路径参数
var updatedDoc Document
reqBody, _ := ioutil.ReadAll(r.Body)
json.Unmarshal(reqBody, &updatedDoc)
var document Document
vars := mux.Vars(r)
id := vars["id"]
if result := Db.First(&updatedDoc, id); result.Error != nil {
fmt.Println(result.Error)
}
document.Name = updatedDoc.Name
Db.Save(&document)
json.NewEncoder(w).Encode(&updatedDoc)
}
希望这能帮到你！
英文:
I have two tables users and documents. They are related in such a way that each document must belong to a user using a one to many relationship. When I try updating a document I get the following error
> ERROR: insert or update on table "documents" violates foreign key
> constraint "fk_users_documents" (SQLSTATE 23503)
Here are my structs definition and update function
type User struct {
gorm.Model
Name string
Email string
Password string
Documents []Document
}
type Document struct {
gorm.Model
Name string
UserID uint
}
//Update document by id
func (h handler)UpdateDocument(w http.ResponseWriter, r *http.Request) {
// once again, we will need to parse the path parameters
var updatedDoc Document
reqBody, _ := ioutil.ReadAll(r.Body)
json.Unmarshal(reqBody, &updatedDoc)
var document Document
vars := mux.Vars(r)
id := vars["id"]
if result := Db.First(&updatedDoc, id); result.Error != nil {
fmt.Println(result.Error)
}
document.Name=updatedDoc.Name
Db.Save(&document)
json.NewEncoder(w).Encode(&updatedDoc)
}
答案1
得分: 1
你正在调用Db.Save(&document)，但是document只有Name字段被填充。这意味着UserID被设置为0。我猜你在User表中没有任何ID为0的用户，因此这违反了外键约束。
在更新文档时，UserID字段应该始终设置为一个现有的用户，否则查询将失败。
不管怎样，我建议你学习一些数据库和Golang的基础知识，因为你发布的代码相当混乱。
英文:
You are calling Db.Save(&document) but document has only its Name field populated. This means that the UserID is set to 0. I'm guessing you don't have any user with ID 0 present in the User table, therefore this violates the foreign key constraint.
The UserID field shall always be set to an existing user when updating a document otherwise the query will fail.
Regardless of this, I'd suggest you to study a bit of database and golang basics because the code you posted is quite messy.
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