I am using RIA Service in our Silverlight application. Database entities are not directly exposed to a client but I have a set of POCO classes for it. Then in CRUD methods for these POCO classes they are converted to database entities and saved to database. The problem arises on the server side when client creates 2 new POCO entities which are related. Insert method is called on the server for each POCO entity separately and I may create corresponding new database entities there and add them to object context. But I see no way to add relation between these created database entities. Is there a solution for that?

例如,我有这2个组织实体(简化):

[DataContract(IsReference = true)]
public partial class Process
{
    [DataMember]
    [Key]
    public string Name
    {
       get; set;
    }

    [DataMember]
    public long StepId
    {
       get; set;
    }

    [DataMember]
    [Association("StepProcess", "StepId", "Id", IsForeignKey=true)]
    public Step Step
    {
       get; set;
    }
}

[DataContract(IsReference = true)]
public partial class Step
{
    [DataMember]
    [Key]
    public long Id
    {
       get; set;
    }

    [DataMember]
    public string Name
    {
       get; set;
    }
}

在我的领域服务类别中,我有这2种方法:

public void InsertProcess(Process process)
{
    var dbProcess = new DBProcess();
    dbProcess.Name = process.Name;
    //dbProcess.StepId = process.StepId;  Cannot do that!
    this.ObjectContext.AddToDBProcess(dbProcess);
}

public void InsertStep(Step step)
{
    var dbStep = new DBStep();
    dbStep.Name = step.Name;
    this.ObjectContext.AddToDBSteps(dbStep);

    this.ChangeSet.Associate<Step, DBStep>
            (step, dbStep, (dto, entity) =>
            {
                dto.Id = entity.Id;
            });
}

Client adds a new Process, then creates and adds a new Step to it and then calls SubmitChanges(). Process.StepId is not filled with a correct value as there is no correct Step.Id for the newly created step yet, so I cannot just copy this value to database entity. So the question is how to recreate relations between newly created database entities the same as they are in newly created DTOs?

我知道组成归属,但不适合我们。 进程和步骤都是独立的实体(即可能没有进程就存在步骤)。