软删除级联不起作用

Question

Objective: If a User is marked deleted in a soft delete, his calendar should also be marked deleted.

structs:

type User struct {
    gorm.Model
    Username  string
    FirstName string
    LastName  string
    Calendar  Calendar
}

type Calendar struct {
    gorm.Model
    Name   string
    UserID uint
}

constraint:

db.Model(&Calendar{}).AddForeignKey("user_id", "users(id)", "CASCADE","CASCADE")

Problem:

A hard delete works: Both the user and his calendar are deleted (records are gone)

db.Exec("Delete from users where id=3")

A soft delete does not work as anticpated:

db.Where("id = ?", 3).Delete(&User{})

With a soft delete,

1. the user table field => deleted_at is dated.
2. the calendar table =? deleted_at is blank

Any ideas?

Answer 1

A soft delete means gorm do not remove your data. It only mark a non-zero DeleteAt timestamp. That is not supported by database directly. So foreign key has no effect here.

That means you need to manually implement the cascaded delete yourself, like this:

func DeleteUser(db *gorm.DB, id int) error {
  tx := db.Begin()
  if tx.Where("id = ?", id).Delete(&User{}); tx.Error != nil {
    tx.Rollback()
    return tx.Error
  }
  // Changed this line
  // if tx.Where("user_id = id", 3).Delete(&Calendar{}); tx.Error != nil {
     if tx.Where("user_id = ?", id).Delete(&Calendar{}); tx.Error != nil {
    tx.Rollback()
    return tx.Error
  }
  return tx.Commit().Error
}