如何级联(软)删除在GORM中有很多关系?
How to cascade (soft) delete has many relationships in GORM?
我正在使用 GORM 实现一些删除功能。我的想法是级联删除,当父行被删除时,子行也被删除。我试过 delete with select。但它只会删除父记录。
func DeleteProject(db *gorm.DB, id uint) (Project, error) {
var project Project
if err := db.Select(clause.Associations).Delete(&project, id).Error; err != nil {
return Project{}, err
}
return project, nil
}
我有以下型号:
type Project struct {
ID uint `gorm:"primary_key" json:"id"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
DeletedAt gorm.DeletedAt `gorm:"index" json:"deleted_at"`
TicketNumber string `gorm:"size:6;unique;not null" json:"ticketnumber"`
Name string `json:"name"`
MailingList string `json:"mailinglist"`
Environment string `gorm:"not null" json:"environment"`
UserID uint `gorm:"index" json:"user_id"`
Diagrams []Diagram `json:"diagrams"`
}
type Diagram struct {
ID uint `gorm:"primary_key" json:"id"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
DeletedAt gorm.DeletedAt `gorm:"index" json:"deleted_at"`
Data string `json:"data"`
ProjectID uint `gorm:"index" json:"project_id"`
Instances []Instance `json:"instances"`
}
type Instance struct {
ID uint `gorm:"primary_key" json:"id"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
DeletedAt gorm.DeletedAt `gorm:"index" json:"deleted_at"`
Key uint `json:"key"`
DiagramID uint `gorm:"index" json:"diagram_id"`
}
一个项目可以有多个图表,一个图表可以有多个实例。但是当我 运行 DeleteProject
函数时,它只删除 Project
而不是相关的图表和实例。
在这种情况下,如何删除项目及其关联的图表和实例?
我找到了解决方案,但我认为它不是级联删除的最佳选择,它至少解决了我的问题。我编写了以下代码:
首先是 DeleteProject
函数,我在其中遍历所有 Diagrams
并调用 DeleteDiagram
函数,最后我还在删除项目之前清除了与该项目的所有关联。
//Delete a project and it's associations.
func DeleteProject(db *gorm.DB, id uint) (Project, error) {
project, err := GetProject(db, id)
if err != nil {
return Project{}, err
}
if len(project.Diagrams) > 0 {
for _, projectDiagram := range project.Diagrams {
_, err := DeleteDiagram(db, projectDiagram.ID)
if err != nil {
return Project{}, err
}
}
db.Model(&project).Association("Diagrams").Clear()
}
if err := db.Delete(&project, id).Error; err != nil {
return Project{}, err
}
return project, nil
}
DeleteDiagram
做同样的事情,但是 Instances
//Delete a diagram and it's associations.
func DeleteDiagram(db *gorm.DB, id uint) (Diagram, error) {
var diagram, err = GetDiagram(db, id)
if err != nil {
return Diagram{}, err
}
if len(diagram.Instances) > 0 {
db.Model(&diagram).Association("Instances").Clear()
for _, diagramInstance := range diagram.Instances {
_, err := DeleteInstance(db, diagramInstance.ID)
if err != nil {
return Diagram{}, err
}
}
}
if err := db.Delete(&diagram).Error; err != nil {
return Diagram{}, err
}
return diagram, nil
}
希望对您有所帮助。
我正在使用 GORM 实现一些删除功能。我的想法是级联删除,当父行被删除时,子行也被删除。我试过 delete with select。但它只会删除父记录。
func DeleteProject(db *gorm.DB, id uint) (Project, error) {
var project Project
if err := db.Select(clause.Associations).Delete(&project, id).Error; err != nil {
return Project{}, err
}
return project, nil
}
我有以下型号:
type Project struct {
ID uint `gorm:"primary_key" json:"id"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
DeletedAt gorm.DeletedAt `gorm:"index" json:"deleted_at"`
TicketNumber string `gorm:"size:6;unique;not null" json:"ticketnumber"`
Name string `json:"name"`
MailingList string `json:"mailinglist"`
Environment string `gorm:"not null" json:"environment"`
UserID uint `gorm:"index" json:"user_id"`
Diagrams []Diagram `json:"diagrams"`
}
type Diagram struct {
ID uint `gorm:"primary_key" json:"id"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
DeletedAt gorm.DeletedAt `gorm:"index" json:"deleted_at"`
Data string `json:"data"`
ProjectID uint `gorm:"index" json:"project_id"`
Instances []Instance `json:"instances"`
}
type Instance struct {
ID uint `gorm:"primary_key" json:"id"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
DeletedAt gorm.DeletedAt `gorm:"index" json:"deleted_at"`
Key uint `json:"key"`
DiagramID uint `gorm:"index" json:"diagram_id"`
}
一个项目可以有多个图表,一个图表可以有多个实例。但是当我 运行 DeleteProject
函数时,它只删除 Project
而不是相关的图表和实例。
在这种情况下,如何删除项目及其关联的图表和实例?
我找到了解决方案,但我认为它不是级联删除的最佳选择,它至少解决了我的问题。我编写了以下代码:
首先是 DeleteProject
函数,我在其中遍历所有 Diagrams
并调用 DeleteDiagram
函数,最后我还在删除项目之前清除了与该项目的所有关联。
//Delete a project and it's associations.
func DeleteProject(db *gorm.DB, id uint) (Project, error) {
project, err := GetProject(db, id)
if err != nil {
return Project{}, err
}
if len(project.Diagrams) > 0 {
for _, projectDiagram := range project.Diagrams {
_, err := DeleteDiagram(db, projectDiagram.ID)
if err != nil {
return Project{}, err
}
}
db.Model(&project).Association("Diagrams").Clear()
}
if err := db.Delete(&project, id).Error; err != nil {
return Project{}, err
}
return project, nil
}
DeleteDiagram
做同样的事情,但是 Instances
//Delete a diagram and it's associations.
func DeleteDiagram(db *gorm.DB, id uint) (Diagram, error) {
var diagram, err = GetDiagram(db, id)
if err != nil {
return Diagram{}, err
}
if len(diagram.Instances) > 0 {
db.Model(&diagram).Association("Instances").Clear()
for _, diagramInstance := range diagram.Instances {
_, err := DeleteInstance(db, diagramInstance.ID)
if err != nil {
return Diagram{}, err
}
}
}
if err := db.Delete(&diagram).Error; err != nil {
return Diagram{}, err
}
return diagram, nil
}
希望对您有所帮助。