Update HasMany Association failing Gorm - postgresql

Question

When I try to update the Shoppinglist struct with the data I get an "there is no unique or exclusion constraint matching the ON CONFLICT specification (SQLSTATE 42P10)" Error
These are my Structs
type Shoppinglist struct {
Model
ID int `gorm:"primaryKey" json:"id"`
Title string `json:"title"`
Items []Item `json:"items" gorm:"foreignKey:ParentListID;references:ID;"`
Owner string `json:"owner"`
Participants pq.StringArray `gorm:"type:text[]" json:"participants"`
}
type Item struct {
Model
ParentListID int `gorm:"primaryKey" json:"parentListId"`
Title string `json:"title"`
Position int `json:"position"`
Bought bool `json:"bought"`
}
And this is the Code I execute when trying to edit a list
func EditList(id int, data map[string]interface{}) error {
//https://github.com/go-gorm/gorm/issues/3487
shoppinglist := Shoppinglist{
ID: data["id"].(int),
Title: data["title"].(string),
Items: data["items"].([]Item),
Owner: data["owner"].(string),
Participants: data["participants"].([]string),
}
if err := db.Session(&gorm.Session{FullSaveAssociations: true}).Where("id = ?", id).Updates(&shoppinglist).Error; err != nil {
return err
}
return nil
}
This is where I execute the EditList and where I set all the values to pass nito the map:
type Shoppinglist struct {
ID int
Title string
Items []models.Item
Owner string
Participants []string
PageNum int
PageSize int
}
func (s *Shoppinglist) Edit() error {
shoppinglist := map[string]interface{}{
"id": s.ID,
"title": s.Title,
"items": s.Items,
"owner": s.Owner,
"participants": s.Participants,
}
return models.EditList(s.ID, shoppinglist)
}
Before I was just using a []string instead of []Item and that was working perfectly. Now everything updates except for the []Item
These are the SQL Queries executed:
UPDATE "shoppinglists" SET "modified_on"=1628251977096,"title"='kjhdsfgnb',"owner"='janburzinski1#gmail.com',"participants"='{}' WHERE id = 517687 AND "id" = 517687
INSERT INTO "items" ("created_on","modified_on","deleted_at","title","position","bought","parent_list_id") VALUES (1628251977,1628251977116,NULL,'dfkjhgndfjkg',1,false,517687),(1628251977,1628251977116,NULL,'dfgh123',2,true,517687) ON CONFLICT ("parent_list_id") DO UPDATE SET "created_on"="excluded"."created_on","modified_on"="excluded"."modified_on","deleted_at"="excluded"."deleted_at","title"="excluded"."title","position"="excluded"."position","bought"="excluded"."bought" RETURNING "parent_list_id"
I would really like to know how to Update a Relation in Gorm or why this isn't working because I've been looking through all the Association Issues on Github and Stackoverflow and didn't find a answer that worked for me.

Answer 1

The first problem I see here is that your Item has no ID but uses the ParentListID as primary key. That means you can only have one Item for each parent which defeats the purpose of having an array.
Create an ID field (used as primary key) for items and if there's still issues with your approach, please update the question.
PS: would have left this in a comment, but can't.

Answer 2

I just needed to add the * to the []Item and fix the problem with the primarykey and remove the reference.
type Shoppinglist struct {
Model
ID int `gorm:"primaryKey" json:"id"`
Title string `json:"title"`
Items []*Item `json:"items" gorm:"foreignKey:ParentListID;"`
Owner string `json:"owner"`
Participants pq.StringArray `gorm:"type:text[]" json:"participants"`
}
type Item struct {
Model
ID int `gorm:"primaryKey" json:"id"`
ParentListID int `json:"parentListId"`
ItemID int `json:"itemId"`
Title string `json:"title"`
Position int `json:"position"`
Bought bool `json:"bought" gorm:"default:false"`
}