Does EF upsert have to be done manually?

Question

I want to upsert reference members of an existing entity.

Do I have to write specific code for the upsert?

meaning: I have to check if I'm handling an existing reference member or a new one.

Is there any other simple way to do so?

What happens when you do only Save ?

  public void SaveCofiguration(MamConfiguration_V1Ui itemUi)         {             var itemEf = mMamConfiguration_V1UiToEfConvertor.ConvertToNewEf(itemUi);              using (var maMDBEntities = new MaMDBEntities())             {                 IDal<MamConfiguration_V1> mamConfigurationDal = mDalFactory.GetDal<MamConfiguration_V1>(maMDBEntities);                  mamConfigurationDal.Save(itemEf);             }         }           public MamConfiguration_V1 GetById(object id)         {                            id.ThrowIfNull("id");                  int configurationId = Convert.ToInt32(id);                  var result =                     mMaMDBEntities.MamConfiguration_V1.SingleOrDefault(item => item.ConfigurationId == configurationId);                  return result;          }         public MamConfiguration_V1 Save(MamConfiguration_V1 item)         {                  item.ThrowIfNull("item");                  var itemFromDB = GetById(item.ConfigurationId);                  if (itemFromDB != null)                 {                     UpdateEfItem(itemFromDB, item);                     // if (mMaMDBEntities.ObjectStateManager.GetObjectStateEntry(itemFromDB).State == EntityState.Detached) //                    {   //                      mMaMDBEntities.MamConfiguration_V1.AddObject(itemFromDB);     //                }                      // Attached object tracks modifications automatically                     mMaMDBEntities.SaveChanges();                      return item;                 }             private void UpdateEfItem(MamConfiguration_V1 itemFromDb, MamConfiguration_V1 itemFromUi)             {                 itemFromDb.UpdatedDate = DateTime.Now;                  itemFromDb.Description = itemFromUi.Description;                  itemFromDb.StatusId = itemFromUi.StatusId;                  itemFromDb.Name = itemFromUi.Name;                  itemFromDb.NumericTraffic = itemFromUi.NumericTraffic;                  itemFromDb.PercentageTraffic = itemFromUi.PercentageTraffic;                  itemFromDb.Type = itemFromUi.NumericTraffic;                  foreach (var item in itemFromDb.MamConfigurationToBrowser_V1.ToList())                 {                     if (itemFromUi.MamConfigurationToBrowser_V1.All(b => b.BrowserVersionId != item.BrowserVersionId))                     {                         mMaMDBEntities.MamConfigurationToBrowser_V1.DeleteObject(item);                     }                 }                  for (int i = 0; i < itemFromUi.MamConfigurationToBrowser_V1.Count; i++)                 {                     var element = itemFromUi.MamConfigurationToBrowser_V1.ElementAt(i);                     var item = itemFromDb.MamConfigurationToBrowser_V1.SingleOrDefault(b => b.BrowserVersionId == element.BrowserVersionId);                     if (item != null)                     {                         // copy properties from element to item                     }                     else                     {                         element.Browser = mMaMDBEntities.Browsers.Single(browserItem =>                             browserItem.BrowserID == element.BrowserID);                          //element.MamConfiguration_V1 = itemFromDb;                          //have also tried: element.MamConfiguration_V1 = null;                          //element.MamConfiguration_V1Reference = null;                          itemFromDb.MamConfigurationToBrowser_V1.Add(element);                     }                 }             } 

But I would have expecte Save(itemUi) and SaveChanges() to work fine. No?

Answer 1

public void InsertOrUpdate(DbContext context, UEntity entity) {     context.Entry(entity).State = entity.Id == 0 ?                                    EntityState.Added :                                    EntityState.Modified;     context.SaveChanges(); } 

http://forums.asp.net/t/1889944.aspx/1

Answer 2

To avoid the overhead of a query and then insert, or throwing exceptions, you can take advantage of the underlying database support for merges or upserts.

This nuget package does the job pretty well: https://www.nuget.org/packages/FlexLabs.EntityFrameworkCore.Upsert/

Github: https://github.com/artiomchi/FlexLabs.Upsert

Example:

DataContext.DailyVisits     .Upsert(new DailyVisit     {         // new entity path         UserID = userID,         Date = DateTime.UtcNow.Date,         Visits = 1,     })     // duplicate checking fields     .On(v => new { v.UserID, v.Date })     .WhenMatched((old, @new) => new DailyVisit     {         // merge / upsert path         Visits = old.Visits + 1,     })     .RunAsync(); 

The underlying generated sql does a proper upsert. This command runs right away and does not use change tracking, so that is one limitation.