[Freebase-discuss] question on freebase MQL manual

[Yury Katkov]

Hi there!

Thanks for the great explanation! It seems that quadruples allows us
to represent ternary relations between objects - I see, that's really
useful for multi-language data representation.
http://wiki.freebase.com/wiki/Data_dumps helps very much, thanks!

Thanks you both for your help!

On Sun, Sep 18, 2011 at 10:08 PM, Roland Bouman <roland.bouman at gmail.com> wrote:
> Hi Yury, all,
>
> On Sun, Sep 18, 2011 at 7:28 PM, Yury Katkov <katkov.juriy at gmail.com> wrote:
>> 1) What is the difference between To node and Value column? I tried to
>
> I like to think of the quads as subject - predicate - object triples
> (like in RDF) where the last two columns are used to capture several
> aspects of the object.
> Sometimes, only identity is captured. In that case, only the "to node"
> column holds a value (which will usually be the mid).
> Sometimes, only a scalar value is captured, in which case only the
> "value" column holds that value.
> In many cases, scalar values in the value column are "qualified" by
> the value in the "to node" column - this happens for example for all
> human readable labels, where the to-node column is used to hold the
> identity of the namespace that represents the language in which the
> value in the value column is word occurring in that language (but
> there are more cases where both columns are used - all "keys" use the
> to-node for the key namespace, and the value for the key)
>
> Whether only the to-node, the value, or both are filled depends on the
> value in the property column. I don't know if the freebase type system
> contains any information on what will be the case for a given
> property. If someone else knows, I'd be interested to know this too.
>
>> graphically represent the data about The Police band that were in
>> example but still don't understand which values will be in To column
>> and which - in Value column :
>> http://img835.imageshack.us/img835/3125/drawingr.png . It's very
>> unclear why does the property "name" connects "/en/the/police" and
>> "/lang/en" istead of en/the/police and "The polic" string.
>>
>> 2) Another question is how is this structure is related to the rest of
>> the manual?  It seems that there is no way to differ "To" and "Value"
>> using MQL and there is no mentions of this Metaweb quaruple structure
>> after the second chapter.
>>
>> Sincerely yours,
>>
>> --
>> Yury V. Katkov
>> WikiVote! llc
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>
>
>
> --
> Roland Bouman
> blog: http://rpbouman.blogspot.com/
> twitter: @rolandbouman
>
> Author of "Pentaho Solutions: Business Intelligence and Data
> Warehousing with Pentaho and MySQL",
> http://tinyurl.com/lvxa88 (Wiley, ISBN: 978-0-470-48432-6)
>
> Author of "Pentaho Kettle Solutions: Building Open Source ETL
> Solutions with Pentaho Data Integration",
> http://tinyurl.com/33r7a8m (Wiley, ISBN: 978-0-470-63517-9)
> _______________________________________________
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-- 
Yury V. Katkov
WikiVote! llc