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<DIV dir=ltr align=left><SPAN class=046530623-03062008><FONT face=Arial
color=#0000ff size=2>Sometimes, having a seemingly absurd number of
properties might really be the right answer. If all the properties are distinct
and of value to someone, I don't see a reason not to use
them. The type "chemical compound" has a lot of properties on it
currently, and I doubt it's anything like exhaustive. (There may be some
crossover with the types you're thinking about.) Another type that is going
to have a huge number of properties eventually is "statistical region", which is
essentially a place to stick various types of statistical measures about places;
I think there are less than a dozen now, but it will keep going up as people add
new kinds of data.</FONT></SPAN></DIV>
<DIV><SPAN class=046530623-03062008><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=046530623-03062008><FONT face=Arial color=#0000ff size=2>It
might also be possible (and I say this knowing nothing about materials
science) that you could create several types. For example, if there are some
properties that nearly all materials have in common, you could put those on a
"Material" type; and if there are some properties that only a certain class of
materials have, you could put them on a type "Material Class 1", which could
have "Material" as an included type, and so get those properties as
well.</FONT></SPAN></DIV>
<DIV><SPAN class=046530623-03062008><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=046530623-03062008><FONT face=Arial color=#0000ff
size=2>Jeff</FONT></SPAN></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2></FONT><BR></DIV>
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<FONT face=Tahoma size=2><B>From:</B> data-modeling-bounces@freebase.com
[mailto:data-modeling-bounces@freebase.com] <B>On Behalf Of </B>jerritt
collord<BR><B>Sent:</B> Tuesday, June 03, 2008 3:57 PM<BR><B>To:</B>
data-modeling@freebase.com<BR><B>Subject:</B> [Data-modeling] relationship
type explanations... diagrams?<BR></FONT><BR></DIV>
<DIV></DIV>I'm new here and not sure how normalized I need to think--or what
I'm missing--or if I'm just having a bad day and need to re-read.<BR><BR>Quick
explanation of problem: I'm not an engineer but an area I'm interested in
tangentially is materials science. There are tons and tons of possible
properties as one might imagine and I don't think the right solution is to
create a Material type with ~100 properties slots. Or maybe it
is?<BR><BR>Obviously the physical properties have to integrate with the fairly
complete system of basic Units in freebase... but e.g. there will be a lot of
mechanical properties all with Units that now carry Units of Pressure
designation. <BR><BR>I know this isn't fruitful, but this is what I tried to
do:<BR>-------<BR>type: MaterialPropertyClass<BR>display is
Enumeration<BR>example instances: Mechanical property, Magnetic property,
Chemical property, Health property<BR><BR>type: MaterialProperty <BR>display
is Standard<BR>properties:<BR>* base SI Unit (single value: reference to
appropriate instances of system Unit type)<BR>* alternative units (multiple
values: reference appropriate instances of system Unit types)<BR>*
MaterialPropertyClass (single value: reference to instance of
MaterialPropertyClass, display as disambiguator)<BR>example instances:
Density, Magnetic Susceptibility (many of these topics already exist,
unstructured, in freebase probably via wikipedia)<BR><BR>type:
MaterialPropertyMeasure <BR>display is Compound
(?)<BR>properties:<BR>* Material<BR>* MaterialProperty (single value:
references MaterialProperty)<BR>* MaterialPropretyValue (single value:
floating point number)<BR>* MaterialPropertyUnits (reference to sytem Unit
type)<BR>* MaterialPropretyDesc (single value: text) -- used for non-numeric
Properties, or descriptions of measurements <BR>example instances: Density of
Stainless Steel<BR><BR>type: Material<BR>properties:<BR>* etc.<BR>*
MaterialsPropertyMeasure (multiple values) ? Here's where I fail to
understand... it seems that what I'd want to do is have all the instances of
MaterialPropertyMeasure that reference this material show
up.<BR>----------<BR>Probably too complicated and all but encourages users to
stray from standard units--and unqueryable to boot. <BR><BR>Any guidance for
examples of domains/problems that resolve relationships like these? Basic
reading I need to do more
of?<BR><BR>Thanks,<BR><BR>Jerritt<BR></BLOCKQUOTE></BODY></HTML>