[Data-modeling] Intervals as a primitive data type

[John Giannandrea]

Tom Morris wrote:
> There are a bunch of types with intervals specified using individual
> properties like start_date/end_date, birth_date/death_date, etc.  If
> these were encoded using a single property with an datetime_interval
> as the type, they could be manipulated and compared much more
> directly.


There is a type, /measurement_unit/time_interval which can be used for  
this.
For example  http://www.freebase.com/type/schema/spaceflight/rocket_engine 
  uses it.

The tradeoff seems to be whether it makes a type more or less  
accessible to have specific properties (like date_of_death) or a  
standard encoding which is one ply further out (a CVT).

In the case of date_of_death, that property is actually on a different  
type than the birth which complicates things further.

I agree with you that if there was a standard way to encode a range  
then the query language (and filter UI) could do smarter things with  
ranges.

Perhaps what we really need is a way of having the 'friendly'  
properties 'reach into' a more normative form which standardizes on  
time_interval.

-jg