[Developers] multiple create unless_exists in one query

[John Giannandrea]

The problem is quite fundamental to MQL write.  If there were two  
existing Fredx people, you definitely want MQL to find the one that  
had the existing kid, not the other one.  Yet the act of writing the  
subclause changes the identify of the object that was found in the  
prepare phase.

I expect there will be a follow up to this thread in January when Tim  
returns from vacation, but for now I think the answer is that you have  
to work around this behavior since it is by design.

-jg


On Dec 20, 2007, at 10:31 AM, Arthur van Hoff wrote:

> Hi Alec,
>
> I think you make a good point. However, I still would argue that the
> behavior that is currently implemented is not useful. Take the query  
> you
> outlined. In the current implementation it would result in the wrong
> result UNLESS Fred already existed. If Fred does not exist you would  
> end
> up with two different Freds, which clearly is not what you intended.
>
> Your example (I had to change the name because Fred already existed):
>
> "query":{
>    "id": null,
>    "children": {
>        "id": null,
>        "name": "Fredx's Kid",
>        "create": "unless_exists",
>        "parents": {
>            "id": null,
>            "name": "Fredx",
>            "create": "unless_exists"
>        }
>    },
>    "name": "Fredx",
>    "type": "/people/person",
>    "create": "unless_exists"
> }