EntityFramework populating uniqueidentifier with value "00000000-0000-0000-0000-000000000000"

Question

In my WCF service I am using Entity Framework .NET 4.0, in my database i have this table:

CREATE TABLE [dbo].[Tracking](
    [TrackingID] [uniqueidentifier] ROWGUIDCOL  NOT NULL,   
    ...
 CONSTRAINT [PK_Tracking] PRIMARY KEY CLUSTERED 
(
    [TrackingID] ASC
)
) ON [DATA]
ALTER TABLE [dbo].[Tracking] ADD  CONSTRAINT [DF_Tracking_TrackingID]  DEFAULT (newid()) FOR [TrackingID]
GO

when i insert a record Entity framewrok has prepopulated the TrackingID as "00000000-0000-0000-0000-000000000000". I have setting field property to be Computed and Identity bu no such luck any ideas: here is my code snippet:

using (var context = new DB.PTLEntities())
{
     var tracking = new DB.Tracking();       
     context.Trackings.AddObject(tracking);
     context.SaveChanges();
     trackingID = tracking.TrackingID;
}

Answer 1

Looks like EF doesnt think this column is an identity column so its putting in default(Guid). Take a look here for some details on making a guid an identity column (it actually goes through your exact example) http://leedumond.com/blog/using-a-guid-as-an-entitykey-in-entity-framework-4/

Answer 2

I got same issue. Following solution worked for me.

There is a need to change the StoreGeneratedPattern value for the property in the EF designer. Set it to Identity. This will cause EF to avoid setting the value on an insert, then capture it after the insert is complete.

If your EF version is 4, then you may have trouble with this using the designer only. You may have to edit the .edmx manually and set the StoreGeneratedPattern in the storage model itself.

Example:

< Property Name="EmpId" Type="uniqueidentifier" Nullable="false" StoreGeneratedPattern="Identity" />