[Developers] mediated properties
Robert Cook
robert at metaweb.com
Thu Jul 19 22:27:26 UTC 2007
On Jul 19, 2007, at 3:16 PM, Augusto Callejas wrote:
> robert-
>
> thanks that does clear it up. going by the definition of the meditator
> pattern, does this type qualify as a mediator:
>
> http://www.freebase.com/view/schema?id=/measurement_unit/rect_size
>
> i wouldn't think so since it only has two properties that are of value
> types.
You are right, this is *not* a mediator, just a CVT. One way to tell
in this case, there is nothing 'passing through' it. Put another
way, it has no properties that are reciprocated from the other end.
> another way to state the question is: are all compound value types
> mediators
> (e.g. opposed to all mediators being compund value types)?
Actually, it's the opposite -- Compound Value Types are *both* the
unnamed example you just described and mediators. I think the
problem here is that we don't have a more specific name for your
example, and "compound value" is pretty descriptive for it.
I think you've highlighted a problem. We need some better terminology.
R
> thanks,
> augusto.
>
>
>
> On 7/19/07 2:59 PM, "Robert Cook" <robert at metaweb.com> wrote:
>
>> Augusto --
>>
>> You are asking a very good question. A "mediator" is a data pattern
>> that is represented as a Compound Value Type in Metaweb. In other
>> words, mediators are CVTs that act like an "annotated relationship"
>> between two types. One example is "Marriage", which joins two people
>> together that also stores add start and end dates as metadata.
>>
>> Currently, we don't have a way to annotate which of the two
>> properties represent the "relationship" between two types. That is,
>> a mediator is more of a data idiom that makes sense to the modeler,
>> but has no formal representation in the data store.
>>
>> We've received feedback similar to yours in the past, and we're
>> currently working on a way of making that distinction (while
>> simultaneously solving a few other problems.) We don't yet have an
>> ETA, but know that it's a real priority for us.
>>
>> Robert
>>
>> On Jul 19, 2007, at 2:37 PM, Augusto Callejas wrote:
>>
>>> hi-
>>>
>>> i ran that query but all properties have value "true"
>>> for the "disambiguator" property hint.
>>>
>>> from the type documentation:
>>>
>>> Musical Group Membership is a compound value type which defines
>>> the
>>> relationship between a Musical Artist (a band or collaboration)
>>> and its
>>> Musical Group Members (musicians).
>>>
>>> is there a difference when you say it mediates for all of the
>>> properties
>>> versus when the documentation says it defines relationships between
>>> musical artist and group member? i'm looking for how that
>>> relationship
>>> is captured in the type information. since the disambigurator
>>> property
>>> hint is the same for all properties, it doesn't define the
>>> relationship
>>> i'm looking for.
>>>
>>> thanks,
>>> augusto.
>>>
>>>
>>> On 7/19/07 10:52 AM, "Darin Wilson" <darin at metaweb.com> wrote:
>>>
>>>> Hi Augusto-
>>>>
>>>> A mediating type, or complex value type (CVT), actually mediates
>>>> for
>>>> all of the properties that the type contains; however, the type
>>>> designer can choose which of those properties should be displayed
>>>> when an instance of the type linked from another topic. If you look
>>>> at the type definition of /music/group_membership, you'll see that
>>>> each of the properties has the "Display as disambiguator" box
>>>> checked. This means that the property will be displayed, if the
>>>> data
>>>> is available.
>>>>
>>>> If you look at the instance list for /music/group_membership,
>>>> you'll
>>>> see that some of the instances have years and other don't. That's
>>>> because the "Period (start)" and/or "Period (end)" properties
>>>> haven't
>>>> been filled out yet. If the data were available, it would be
>>>> displayed.
>>>>
>>>> http://www.freebase.com/view/filter?id=%2Fmusic%2Fgroup_membership
>>>>
>>>> To see this programmatically, you can use the following query.
>>>> The /
>>>> freebase/type_hints/mediator property on the type will tell you if
>>>> it's a CVT or not. The /freebase/property_hints/disambiguator on
>>>> the
>>>> properties will tell you if the value of the property should be
>>>> displayed.
>>>>
>>>> {
>>>> "query":[{
>>>> "id":"/music/group_membership",
>>>> "type":"/type/type",
>>>> "/freebase/type_hints/mediator":null,
>>>> "properties":[{
>>>> "id":null,
>>>> "/freebase/property_hints/disambiguator":null
>>>> }]
>>>> }]
>>>> }
>>>>
>>>> HTH,
>>>> Darin
>>>>
>>>>
>>>> On Jul 19, 2007, at 10:05 AM, Augusto Callejas wrote:
>>>>
>>>>> hi-
>>>>>
>>>>> regarding mediating types, how do i determine what two other types
>>>>> it is mediating for? for instance, there is the complex type:
>>>>>
>>>>> http://freebase.com/view/filter?id=/music/group_membership
>>>>>
>>>>> reading the type description reveals that it relates these two
>>>>> types:
>>>>>
>>>>> /music/group_member (via property /music/group_membership/
>>>>> member)
>>>>> /music/musical_group (via property /music/group_membership/
>>>>> group)
>>>>>
>>>>> how do i determine this programmatically? at first, i was
>>>>> going to
>>>>> use that fact that these two properties have "unique":true, but
>>>>> so is the case for two other properties:
>>>>>
>>>>> /music/group_membership/start
>>>>> /music/group_membership/end
>>>>>
>>>>> how can i make the distinction?
>>>>>
>>>>> thanks,
>>>>> augusto.
>>>>>
>>>>>
>>>>> On 6/28/07 3:46 PM, "Dae Park" <daepark at metaweb.com> wrote:
>>>>>
>>>>>> We perform a "schema query" for each type a topic is an instance
>>>>>> which includes a query for each property and their
>>>>>> expected_type. If
>>>>>> the expected_type is marked as a mediator then we go another ply
>>>>>> out
>>>>>> and ask for the property's expected_type's disambiguating
>>>>>> properties.
>>>>>>
>>>>>> {
>>>>>> id: #topic_id
>>>>>> type: [{
>>>>>> id: null,
>>>>>> properties: [{
>>>>>> id: null,
>>>>>> master_property: null,
>>>>>> reverse_property: null,
>>>>>> unique: null,
>>>>>> expected_type: {
>>>>>> id: null,
>>>>>> "/freebase/type_hints/mediator": null,
>>>>>> properties: [{
>>>>>> master_property: null,
>>>>>> reverse_property: null,
>>>>>> id: null,
>>>>>> unique: null,
>>>>>> "/freebase/type_hints/disambiguator": true
>>>>>> }}
>>>>>> }
>>>>>> }]
>>>>>> }]
>>>>>> }
>>>>>>
>>>>>> When displaying these mediator properties (sub_properties) from a
>>>>>> topic's property:
>>>>>>
>>>>>> if the topic_property and sub_property are reciprocal of one
>>>>>> another:
>>>>>> if sub_property is unique:
>>>>>> skip
>>>>>> else:
>>>>>> foreach value in sub-property:
>>>>>> if value == topic we're viewing:
>>>>>> continue:
>>>>>> display value
>>>>>>
>>>>>>
>>>>>> Two properties (prop1, prop2) are reciprocal's of one another if:
>>>>>>
>>>>>> prop1.reverse_property == prop2
>>>>>> or
>>>>>> prop2.master_property == prop1
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Jun 28, 2007, at 1:15 PM, Steve Sak wrote:
>>>>>>
>>>>>>>
>>>>>>> How does the freebase.com "person" web pages "know" to
>>>>>>> display the
>>>>>>> name
>>>>>>> of the spouse/sibling or the name of the organization a person
>>>>>>> worked
>>>>>>> for under "employment history"? Hard-coded?
>>>>>>>
>>>>>>> Nick Thompson wrote:
>>>>>>>> in general, i don't think your question has a well-defined
>>>>>>>> answer -
>>>>>>>> there's no reason for the system to believe that
>>>>>>>> /business/employment_tenure/company is more relevant than
>>>>>>>> /business/employment_tenure/title, for example. you could be
>>>>>>>> looking
>>>>>>>> for a list of people at a particular company, in which case
>>>>>>>> the job
>>>>>>>> title would more interesting.
>>>>>>>>
>>>>>>>> so, you might rule out /business/employment_tenure/person from
>>>>>>>> context
>>>>>>>> as chris described, but that doesn't determine a unique "other
>>>>>>>> side".
>>>>>>>> that's the nature of compound value types - if a relationship
>>>>>>>> only
>>>>>>>> had two sides, it would probably be modeled as a single link
>>>>>>>> instead
>>>>>>>> of being mediated by a compound value object.
>>>>>>>>
>>>>>>>> nick
>>>>>>>>
>>>>>>>> Steve Sak wrote:
>>>>>>>>> So, if I'm looking at /people/person/employment_history how
>>>>>>>>> would I
>>>>>>>>> determine that the relevant property is
>>>>>>>>> /business/employment_tenure/company?
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Alec Flett wrote:
>>>>>>>>>> I want to add that checking by is only valid if you know
>>>>>>>>>> you're
>>>>>>>>>> coming
>>>>>>>>>> in and out on the same property (as is the case with
>>>>>>>>>> marriage)
>>>>>>>>>> - if
>>>>>>>>>> the properties are different, you need to look at master/
>>>>>>>>>> reverse
>>>>>>>>>> properties because you can imagine a director who also
>>>>>>>>>> produced a
>>>>>>>>>> movie - if you were just going by ids, looking at the
>>>>>>>>>> relationship of
>>>>>>>>>>
>>>>>>>>>> "Who is the /director/ of this movie /produced by/ Martin
>>>>>>>>>> Scorsese?" -
>>>>>>>>>> you might get Martin Scorsese back, but that doesn't mean
>>>>>>>>>> that
>>>>>>>>>> "director" is the reverse of "produced by".
>>>>>>>>>>
>>>>>>>>>> Alec
>>>>>>>>>>
>>>>>>>>>> Christopher R. Maden wrote:
>>>>>>>>>>> Steve Sak wrote:
>>>>>>>>>>>
>>>>>>>>>>>> To restate the question: given a mediator object how do I
>>>>>>>>>>>> determine
>>>>>>>>>>>> which property is the one it's mediating? For example,
>>>>>>>>>>>> type A
>>>>>>>>>>>> has a
>>>>>>>>>>>> mediator M that has a bunch of properties mediates
>>>>>>>>>>>> between A
>>>>>>>>>>>> and
>>>>>>>>>>>> another
>>>>>>>>>>>> object. How do I determine which property of M is the one
>>>>>>>>>>>> that
>>>>>>>>>>>> points
>>>>>>>>>>>> to the other object being mediated?
>>>>>>>>>>>>
>>>>>>>>>>> Mediators, or compound value types, are not especially
>>>>>>>>>>> different
>>>>>>>>>>> from any other type; the UI treats them a little
>>>>>>>>>>> differently,
>>>>>>>>>>> but
>>>>>>>>>>> that’s it.
>>>>>>>>>>>
>>>>>>>>>>> But I think you are asking about instances rather than
>>>>>>>>>>> types,
>>>>>>>>>>> correct? In other words, Arnold Schwarzenegger connects to a
>>>>>>>>>>> marriage, and that marriage connects to two people, both
>>>>>>>>>>> Arnold
>>>>>>>>>>> Schwarzenegger and Maria Shriver. How can you tell which
>>>>>>>>>>> of the
>>>>>>>>>>> spouses is the one you started from?
>>>>>>>>>>>
>>>>>>>>>>> The only way to do that, really, is by looking at the IDs.
>>>>>>>>>>>
>>>>>>>>>>> {
>>>>>>>>>>> "query": {
>>>>>>>>>>> "id": null,
>>>>>>>>>>> "name": "Arnold Schwarzenegger",
>>>>>>>>>>> "spouse_s": [
>>>>>>>>>>> {
>>>>>>>>>>> "spouse": [
>>>>>>>>>>> {
>>>>>>>>>>> "id":null,
>>>>>>>>>>> "name":null
>>>>>>>>>>> }
>>>>>>>>>>> ],
>>>>>>>>>>> "type":"/people/marriage"
>>>>>>>>>>> }
>>>>>>>>>>> ],
>>>>>>>>>>> "type":"/people/person"
>>>>>>>>>>> }
>>>>>>>>>>> }
>>>>>>>>>>>
>>>>>>>>>>> {
>>>>>>>>>>> "result": {
>>>>>>>>>>> "spouse_s": [
>>>>>>>>>>> {
>>>>>>>>>>> "spouse": [
>>>>>>>>>>> {
>>>>>>>>>>> "id": "#9202a8c04000641f80000000001da07e",
>>>>>>>>>>> "name": "Maria Shriver"
>>>>>>>>>>> },
>>>>>>>>>>> {
>>>>>>>>>>> "id": "#9202a8c04000641f8000000000006567",
>>>>>>>>>>> "name": "Arnold Schwarzenegger"
>>>>>>>>>>> }
>>>>>>>>>>> ],
>>>>>>>>>>> "type": "/people/marriage"
>>>>>>>>>>> }
>>>>>>>>>>> ],
>>>>>>>>>>> "type": "/people/person",
>>>>>>>>>>> "id": "#9202a8c04000641f8000000000006567",
>>>>>>>>>>> "name": "Arnold Schwarzenegger"
>>>>>>>>>>> }
>>>>>>>>>>> }
>>>>>>>>>>>
>>>>>>>>>>> You can see that one of the spouses in the marriage has the
>>>>>>>>>>> same ID
>>>>>>>>>>> as the person with whom you started, and that the other is
>>>>>>>>>>> different.
>>>>>>>>>>>
>>>>>>>>>>> Unfortunately, there’s not really an automatic way to say
>>>>>>>>>>> “get all
>>>>>>>>>>> of the values of these properties except the ones that point
>>>>>>>>>>> back
>>>>>>>>>>> to the parent within the scope of this query.”
>>>>>>>>>>>
>>>>>>>>>>> HTH,
>>>>>>>>>>> Chris
>>>>>>>>>>>
>>>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Steven G Sak
>>>>>>> Applied Minds, Inc.
>>>>>>> 11718 Bowman Green Drive
>>>>>>> Reston, Virginia 20190
>>>>>>> o: (703) 483-2207
>>>>>>> c: (703) 626-2557
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Developers mailing list
>>>>>>> Developers at freebase.com
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>>>>>
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