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Can't update persistent object

7/16/2006 11:17:31 PM

Marc

8 posts

Can't update persistent object
Modified By Mirko on 7/18/2006 10:17:12 AM)

Hi!

I use this code to update a persistent object:

PersistenceManager pm = new PersistenceManager();
pm.MakePersistent(odlSalutationLetter);
pm.Save();

After pm.Save() I get this exception:

MakePersistent: Object is already persistent: [Type = ...|Id = ...]"
Source="NDO"
...

I use NDO Professional version 1.2.0.0.

What have I done wrong?

Best Regards,

Marc Haid

7/17/2006 10:55:04 AM

Mirko

109 posts

Re: Can't update persistent object
Modified By Mirko on 7/17/2006 10:55:27 AM)

Hi Marc,

updating an object simply requires calling Save().

MakePersistent is only used to store an object in the first place, thus making it persistent.

If you change a persistent object, the object marks itself as Dirty and NDO updates the data row during the next call to Save().

I hope, that helps!

Best Regards:
Mirko

7/17/2006 10:38:13 PM

Marc

8 posts

Re: Can't update persistent object
Modified By Marc on 7/17/2006 10:39:13 PM)

Hi!

I changed the code, so that MakePersistent only is called when the object has the NDOObjectState = Transistent.

If I update only the Save() method is called, but the value I changed isn't updated at the database.

Must I do something else?

Best Regards,

Marc Haid

7/18/2006 10:15:33 AM

Mirko

109 posts

Re: Can't update persistent object

Hi Marc,

creating and changing an object are two different scenarios.

1. Creating:

Employee e = new Employee();
// Setting the properties occurs
// the UI
e.FirstName = "Mirko";
e.LastName = "Matytschak";
pm.MakePersistent(e);
pm.Save();

2. Changing

// e might be retrieved by a query
// Setting the properties normally
// occurs in the UI
e.FirstName = "Johnny";
e.LastName = "Winter";
pm.Save();
// new state of e is in the database

Have a look at our Tutorial application to see, how these things work.

Best Regards
Mirko

7/18/2006 11:36:34 AM

Marc

8 posts

Re: Can't update persistent object

Hi Mirko,

here is my code snippet for creating and changing respectively:

public void Save()
{
// Es wurde keine Briefanrede eingegeben
if (odlSalutationLetter.SalutationLetter != "" && odlSalutationLetter.SalutationLetter != null)
{
PersistenceManager pm = new PersistenceManager();
if (ObjectHelper.GetObjectId(odlSalutationLetter) == null)
{
pm.MakePersistent(odlSalutationLetter);
}
pm.Save();
}
}

I think it should combine the two possibilities.

I think the problem might be the data binding. I generate a NDOArrayList of objects, bind it to an GridView and I use "sender.DataSource(e.NewEditIndex)" to get the selected object from the Grid and put it to my BusinessLogic ("oblSalutatuionLetter.getObject(sender.DataSource(e.NewEditIndex))").

The GUI is an ASP.NET site and the Grid is placed at an user control.

Is that a possibility for the problem?

Best Regrads,

Marc Haid

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Developing with NDO

Can't update pe...