> Thanks David.

> I am struggling with how I handle parent child, such as order header,
> line, and shipment. An order line cannot exist outside a header. So we want
> to make the URI something like:
> /orders/123/lines/1/shipments/1

> In the schema, I want to do something like this:

> "orders": {
>   "properties": {
>     "orderId":...
>     "lines": {
>       "items": {
>         "properties": {
>           "lineId":...
>           "shipments": {
>              "items": {
>                "properties" {"shipmentId":...},
>                "links": [
>                  {"rel": "self", "href":
> "/orders/{orderId}/lines/{lineId}/shipments/{shipmentId}"}
>                ]
>              }
>            }
>         },
>         "links": [
>            {"rel": "self", "href": "/orders/{orderId}/lines/{lineId}"}
>         ]
>       }
>     }
>   },
>   "links":[
>     {
>       "rel": "self", "href": "/orders/{orderId}"
>     }
>    ]
> }

> but this is not supported. Is there any alternative?
> Can I reference the parent schema's self link from a child's schema?

> On Saturday, November 10, 2012 4:34:40 AM UTC-8, Geraint (David) wrote:

>> 1. No - you can only reference the immediate properties of an object.

>> 2. According to the version 3 specification, yes.  I'm not sure I like
>> it, though - to me, schemas should describe items.  However, that's how
>> draft version 3 was written, and I'm not going to try and change it if
>> people find it useful.

>> On Friday, November 9, 2012 8:27:30 PM UTC, Ning wrote:

>>> Thanks for the clarification.

>>> 1. Is it possible to reference the property from the parent schema
>>> inside a nested schema's link? Take my previous example, if I expand it:

>>> "departments": {
>>>     "name": "Department",
>>>     "properties": {
>>>       "departmentId": ...,
>>>       "departmentName": ...,

>>>       "locationId": {

>>>         "type": integer

>>>       },

>>>       "employees": {

>>>         "items": {

>>>           "properties": {...},

>>>           "links": [

>>>             {"rel": "location",

>>>              "href": "/locations/{locationId}},

>>>           ]

>>>         }

>>>       }
>>>     }
>>>   }

>>> Is the location link valid?

>>> 2. Regarding the "instances" link. Using the above example, I can have a
>>> link:
>>> {"rel": "instances",
>>>  "href": "/departments"}
>>> for the department schema, and GET /departments is supposed to return a
>>> list of departments. Is it right?

>>> Thanks.

>>> Ning

>>> On Friday, November 9, 2012 1:22:20 AM UTC-8, Geraint (David) wrote:

>>>> A couple of things worth noting:  The client is under no obligation to
>>>> believe that the data for the furniture items at the same as the data from
>>>> the claimed URI.  It is a useful hint.

>>>> Also, the "self" link is only used because the *complete data* for the
>>>> items of furniture is included, so the client only needs to make one
>>>> request.  If you only included a small portion of it, then a "full" link
>>>> would be more appropriate, indicating that the client should visit that URI
>>>> to get the rest of the data.

>>>> On Friday, November 9, 2012 9:18:39 AM UTC, Geraint (David) wrote:

>>>>> The "self" link is often not very useful if you have just fetched the
>>>>> document from that URI.  As you say, you already have the URI, so what does
>>>>> the "self" link provide?

>>>>> However, it is more useful when you opened the data from somewhere
>>>>> else, and do *not* know the URI for it.  In that case, the "self"
>>>>> link is just a way of specifying that URI from the item data.

>>>>> It's also useful when you have composite data.  For instance, say we
>>>>> have this document fetched from /rooms/4:
>>>>> {
>>>>>     "roomId": 4,
>>>>>     "name": "The lobby",
>>>>>     "furniture": [
>>>>>         {
>>>>>             "furnitureId": 3563,
>>>>>             "roomId": 4,
>>>>>             "name": "Receptionist's desk",
>>>>>             "type": "desk",
>>>>>             ...
>>>>>         },
>>>>>         {
>>>>>             "furnitureId": 2031,
>>>>>             "roomId": 4,
>>>>>             "name": "A wheely chair",
>>>>>             "type": "chair",
>>>>>             ...
>>>>>         },
>>>>>     ]
>>>>> }

>>>>> This document contains the *full* details of all the furniture in
>>>>> that room, bundled up inside it.  However, if I want to interact with a
>>>>> particular piece of furniture, how do I do that?  I could use a JSON
>>>>> Pointer fragment, but then if I moved a piece of furniture from one room to
>>>>> the other, nobody else could tell it was the same piece of furniture.

>>>>> So I define a "self" link on the furniture items:
>>>>> {
>>>>>     "title": "Room",
>>>>>     "type": "object",
>>>>>     "properties": {
>>>>>         "furniture": {
>>>>>             "type": "array",
>>>>>             "items": {
>>>>>                 "title": "Furniture",
>>>>>                 "type": "object",
>>>>>                 "properties": { ... },
>>>>>                 "links": [
>>>>> *                    {
>>>>> *
>>>>> *                        "rel": "self",
>>>>> *
>>>>> *                        "href": "/furniture/{furnitureId}"
>>>>> *
>>>>> *                    },
>>>>> *
>>>>>                     {
>>>>>                         "rel": "parent",
>>>>>                         "href": "/room/{roomId}"
>>>>>                     }
>>>>>                 ]
>>>>>             }
>>>>>         }
>>>>>     }
>>>>> }

>>>>> Now, if I want to move the wheely chair to another room, I don't have
>>>>> to delete the one in the lobby, and create a new one somewhere else,
>>>>> because this chair has a unique URI of its own.  And what's more, I *
>>>>> know* this URI, even though it was served up to me embedded inside
>>>>> another document.

>>>>> So I can probably just modify the chair itself using a PUT request:
>>>>> PUT /furniture/2031
>>>>> {
>>>>>     "furnitureId": 2031,
>>>>>     "roomId": 15,
>>>>>     "name": "The wheely chair from the lobby",
>>>>>     "type": "chair",
>>>>>     ...
>>>>> }

>>>>> Presumably, the server would at this point stop including the chair in
>>>>> the furniture listing for the lobby (#4), and start including it in a
>>>>> different room (#15).

>>>>> On Thursday, November 8, 2012 11:30:35 PM UTC, Ning wrote:

>>>>>> I am trying to figure out how to use the links for rest APIs.

>>>>>> Suppose that I have a resource /departments and /departments/123 lets
>>>>>> me access a particular department 123.

>>>>>> How will be the self link used by a consumer? say if I have:

>>>>>> "departments": {
>>>>>>     "name": "Department",
>>>>>>     "properties": {
>>>>>>       "departmentId": {
>>>>>>         "type": "integer",
>>>>>>         "description": "department identifier"
>>>>>>       },
>>>>>>       "departmentName": {
>>>>>>         "type": "string",
>>>>>>         "description": "department name"
>>>>>>       }
>>>>>>     }
>>>>>>     "links": [
>>>>>>       {
>>>>>>         "rel": "self",
>>>>>>         "href": "{departmentId}"
>>>>>>       }
>>>>>>     ]
>>>>>>   }

>>>>>> The self link is against a json instance, so I should already have
>>>>>> the instance URI, which is /departments/123. What does the self link
>>>>>> provide?