Golang GORM Cascade Delete to Nested Fields - go

Question

Main Model:
type Page struct {
ID int `gorm:"primarykey" json:"id"`
Title string `gorm:"unique;not null" json:"title"`
LocalizedPageTitles []LocalizedPageTitle `gorm:"constraint:OnUpdate:CASCADE,OnDelete:CASCADE;" json:"localizedPageTitles"`
Paragraphs []Paragraph `gorm:"constraint:OnUpdate:CASCADE,OnDelete:CASCADE;" json:"paragraphs"`
CreatedAt time.Time `json:"-"`
UpdatedAt time.Time `json:"-"`
DeletedAt gorm.DeletedAt `gorm:"index" json:"-"`
}
First Child:
type Paragraph struct {
ID uint `gorm:"primarykey" json:"id"`
Text string `gorm:"unique;not null" json:"text"`
PageID uint `json:"pageId"`
LocalizedParagraphs []LocalizedParagraph `gorm:"constraint:OnUpdate:CASCADE,OnDelete:CASCADE;" json:"localizedParagraphs"`
CreatedAt time.Time `json:"-"`
UpdatedAt time.Time `json:"-"`
DeletedAt gorm.DeletedAt `gorm:"index" json:"-"`
}
Second Child:
type LocalizedParagraph struct {
Localized
ID uint `gorm:"primarykey" json:"id"`
ParagraphID uint `json:"paragraphId"`
CreatedAt time.Time `json:"-"`
UpdatedAt time.Time `json:"-"`
DeletedAt gorm.DeletedAt `gorm:"index" json:"-"`
}
This is how I delete my page entity:
func (p PageRepositoryImpl) Delete(id int) error {
return p.db.Unscoped().Select(clause.Associations).Delete(&entity.Page{ID: id}).Error
}
Above function deletes Page and Paragraphs but how can I remove LocalizedParagraphs automatically?
By the way I'm using Sqlite.
dbmanager.go
func InitSQLite(filePath string) *gorm.DB {
database, err := gorm.Open(sqlite.Open(filePath), &gorm.Config{})
if err != nil {
fmt.Printf("Error:%v", err)
panic("Failed to connect database")
}
autoMigrateDB(database)
return database
}
func autoMigrateDB(db *gorm.DB) {
db.AutoMigrate(
&entity.Page{},
&entity.Paragraph{},
&entity.LocalizedPageTitle{},
&entity.LocalizedParagraph{},
)
}

Answer 1

I couldn't perform this action without delete hooks.
Select(clause.Associations) statement already take care of the one level associations:
func (p PageRepositoryImpl) Delete(id int) error {
return p.db.Unscoped().Select(clause.Associations).Delete(&entity.Page{ID: id}).Error
}
For nested associations, I used delete hook,
here is my solution:
func (page *Page) BeforeDelete(tx *gorm.DB) error {
paragraphs := make([]Paragraph, 0)
err := tx.Where("page_id = ?", page.ID).Find(&paragraphs).Error
if err != nil{
return err
}
ids := make([]int, 0, len(paragraphs))
for _, element := range paragraphs{
ids = append(ids, int(element.ID))
}
lps := make([]LocalizedParagraph,0)
err = tx.Where("paragraph_id IN ?", ids).Unscoped().Delete(&lps).Error
return err;
}