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id generation for a entity mapped with queryview + modificationfunctionmapping

Printed From: IdeaBlade
Category: DevForce
Forum Name: DevForce 2009
Forum Discription: For .NET 3.5
URL: http://www.ideablade.com/forum/forum_posts.asp?TID=1641
Printed Date: 05-Apr-2025 at 11:06am


Topic: id generation for a entity mapped with queryview + modificationfunctionmapping
Posted By: bebe
Subject: id generation for a entity mapped with queryview + modificationfunctionmapping
Date Posted: 11-Feb-2010 at 12:55am
Hi,
 
I have to use a queryview + modificationfunctionmapping for my class. The generation of the ID does not work as soon I exchange the "EntityTypeMapping" with a very simple "QueryView".
 
the mapping with the queryview may look like:
 
<EntitySetMapping Name="TestSet">
       <QueryView>
              select value 
        TestModel.Test(t.testid, t.value)
        from TestModelStoreContainer.test as t
        </QueryView>
...
  + some ModificationFunctionMapping for insert (with ResultBinding) , update and delete
...
</EntitySetMapping>
 
if i use pure entityframework, this works fine:

      using (var ctx = new Model.TestEntities())
   {
       var test = new Model.Test();
       test.value = "test";
       ctx.AddToTestSet(test);
       Assert.LessOrEqual(test.testid, 0);
       ctx.SaveChanges();
       Assert.Greater(test.testid, 0);
   }
if i use Devforce EntityManager, the ID is not generated.
 
    var manager = DomainModel.DomainModelEntityManager.DefaultManager;
    var test2 = manager.CreateEntity<DomainModel.Test>();
    test2.value = "test2";
    test2.EntityAspect.AddToManager();
    Assert.Less(test2.testid, 0);                             // testid == 0  :(
    manager.SaveChanges();         
    Assert.Greater(test2.testid, 0);                          // testid == 0  :(
 
Wenn SaveChanges is executed, the insert-command is executed and the data with the new testid is fetched by the EntityManager. -> there are two instances of test in the chache now. one with testid==0 and the other one with the id generated by the database.
 
Is there any way to use queryview-mapping with the standard id-generator?
 
 


Replies:
Posted By: davidklitzke
Date Posted: 15-Feb-2010 at 3:55pm
Id generatiion does not happen automatically.  That is why no ids are being generated.  Read how to generate ids using an IdGenerator in the Learning Resources (look at "Adding and Deleting" in "Business Object Persistence" and search for "IdGenerator").

Posted By: bebe
Date Posted: 16-Feb-2010 at 6:39am
Hi davidklitzke,
thanks for your reply. Yes, obviously the Id generation does not happen. And I hope, I don't have to implement a id generation mechanism. I would like to use identity keys generated by sql server.
 
The primary key of my table is a sql server identity(1,1) column and the corresponding property in the SSDL has set attribute StoreGeneratedPattern="Identity". 
 
In the "Adding and Deleting Sample" you refere to I read:
Identity Keys
When working with an identity primary key, the statement setting the key value in the code snippet above would simply be omitted. You need do nothing whatsoever to set the key value: DevForce will handle it.
 
unfortunaly, DevForce no longer handles it, as soon I use a queryview for mapping.  I guess the build in devforce identityIdGeneration would work if applied. Is there any way to encourage DevForce to use identityIdGeneration in this scenario?
 
 

Posted By: davidklitzke
Date Posted: 17-Feb-2010 at 4:56pm

It’s likely that the generated data properties for the entity don’t recognize the Id as auto-incrementing.  You can check this by examining the entity property for the Id property in the generated class.  We’ll look into this and open a bug report if necessary.

To workaround this now, you should be able to create your own auto-incrementing Id.   Here’s an example: 

    // Define the new entity property, with the auto-incrementing argument set to true. 

      var newEmployeeIDEntityProperty = new DataEntityProperty<Employee, Int32>("EmployeeID"

       ,false, true, ConcurrencyStrategy.None, true, VerificationSetterOptions.Both);

    // Create the entity and explicitly call GenerateId with the new property.

     Employee emp = entityManager.CreateEntity<Employee>();

      entityManager.GenerateId(emp, newEmployeeIDEntityProperty);

      entityManager.AddEntity(emp);

 

Posted By: bebe
Date Posted: 18-Feb-2010 at 10:20am
Your are right. When I set the isAutoIncrementing to true, ID generation works.
 
Your proposed workaround did well, but I had problems with the corresponding navigation property. I prefere to apply a patch to the autogenerated code as pre-build operation. This works, but I'm looking forward to see DevForce handling this.
 
Thank you for your help.
 


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