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From Nikita Timofeev <>
Subject Re: Question on how to properly create parent-child nested dependent objects?
Date Wed, 20 Sep 2017 12:45:44 GMT
Other option is to create CommunicationType first and then just use it:

CommunicationType type = CommunicationType.find("Email");

CommunicationLog cl = oc.newObject(CommunicationLog.class);

In this case everything will be in one context, and you can freely
commit CommunicationType to DB.

On Wed, Sep 20, 2017 at 3:37 PM, Mike Kienenberger <> wrote:
> I haven't followed the details, so I don't know if using a separate
> object context is necessary, but all you need to do to move a data
> object (in your case "child") to a different context is to call
> parentContext.localObject(childDataObject) which will return
> childDataObjectInParentContext.   Note that this requires either a
> hollow or committed childDataObject as a modified (uncommitted) or new
> (uncommitted) data object's changes only exist in the
> childObjectContext.
> I may also have the syntax for localObject() wrong as I'm probably
> using an older version of Cayenne than you are.
> On Wed, Sep 20, 2017 at 8:30 AM, Andrew Willerding
> <> wrote:
>> I guess my issue is with how independent the commits can be.  Now that I
>> better understand this, my code example works as Nikita suggested (with the
>> fix for my problem with the PrimaryKey table) and if I drop the commit
>> during the creation of the child object otherwise the commit during the
>> child creation will fail because the parent has not yet been assigned with
>> the child object.
>> My objective is that I want the creation of the child to be completely
>> independent of the parent object for this situation. To do this I have to
>> create a new ObjectContext  for the child object to make it independent of
>> the parent's ObjectContext but when I return the newly created child object
>> to the parent object I get the following
>> Caused by: org.apache.cayenne.CayenneRuntimeException: [v.4.0.B1 Jun 02 2017
>> 15:11:18] Cannot set object as destination of relationship communicationType
>> because it is in a different ObjectContext
>>     at
>> org.apache.cayenne.CayenneDataObject.willConnect(
>>     at
>> org.apache.cayenne.CayenneDataObject.setToOneTarget(
>>     at
>>     at
>> com.callistacti.clientbase.Panel.PanelGroups.windowClose(
>> So what I then needed to do is lookup the child object with the same
>> ObjectContext that the parent was using.
>> Out of curiousity, is there any simpler way of doing this?
>> On 19/09/17 09:16 AM, Aristedes Maniatis wrote:
>>> On 19/9/17 11:01PM, Andrew Willerding wrote:
>>>> The CommunicationType object does not yet exist permanently in the
>>>> database table so how or when does it generate the primary key for the
>>>> object to be referenced by another object before it is committed?  I was
>>>> hoping to not have to worry about this as a "high-level" user of Cayenne.
>>> You are right, you don't need to worry about all that. Just create one
>>> context and save it at the end. Cayenne tracks the relationships between
>>> objects with a temporary key internally, but you don't need to think about
>>> that. Once Caynenne commits, everything is assigned proper primary keys and
>>> joined.
>>> Ari

Best regards,
Nikita Timofeev

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