How can I retrieve Id of inserted entity using Entity framework? [closed]

Answer 1

You need to reload the entity after saving changes. Because it has been altered by a database trigger which cannot be tracked by EF. SO we need to reload the entity again from the DB,

db.Entry(MyNewObject).GetDatabaseValues();

Then

int id = myNewObject.Id;

Look at @jayantha answer in below question:

How can I get Id of the inserted entity in Entity framework when using defaultValue?

Looking @christian answer in below question may help too:

Entity Framework Refresh context?

Answer 2

The object you're saving should have a correct Id after propagating changes into database.

Answer 3

When you use EF 6.x code first

    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public Guid Id { get; set; }

and initialize a database table, it will put a

(newsequentialid())

inside the table properties under the header Default Value or Binding, allowing the ID to be populated as it is inserted.

The problem is if you create a table and add the

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]

part later, future update-databases won't add back the (newsequentialid())

To fix the proper way is to wipe migration, delete database and re-migrate... or you can just add (newsequentialid()) into the table designer.

Answer 4

Please refer this link.

http://www.ladislavmrnka.com/2011/03/the-bug-in-storegeneratedpattern-fixed-in-vs-2010-sp1/

You have to set the property of StoreGeneratedPattern to identity and then try your own code.

Or else you can also use this.

using (var context = new MyContext())
{
  context.MyEntities.AddObject(myNewObject);
  context.SaveChanges();

  int id = myNewObject.Id; // Your Identity column ID
}

Answer 5

I come across a situation where i need to insert the data in the database & simultaneously require the primary id using entity framework. Solution :

long id;
IGenericQueryRepository<myentityclass, Entityname> InfoBase = null;
try
 {
    InfoBase = new GenericQueryRepository<myentityclass, Entityname>();
    InfoBase.Add(generalinfo);
    InfoBase.Context.SaveChanges();
    id = entityclassobj.ID;
    return id;
 }

Answer 6

There are two strategies:

1. Use Database-generated ID (int or GUID)

   Cons:

   You should perform SaveChanges() to get the ID for just saved entities.

   Pros:

   Can use int identity.

2. Use client generated ID - GUID only.

   Pros: Minification of SaveChanges operations. Able to insert a big graph of new objects per one operation.

   Cons:

   Allowed only for GUID