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I'm not sure how Temperature and Humidity are related as types beyond 
"extends float". i.e. What tuple definition could alternatively have a 
Temp or a Humidity value?  (I do understand their physical relationship :) )



Gianvito Pio wrote:
> Hi all,
> I just want to ask you if it's possible to define sub types in 
> PostgreSQL (Type inheritance). I found that table inheritance is 
> possible...but I'd like to do it on types.
>
> Example:
> define a type Value and two subtypes Temperature and Humidity and then 
> define a table that has an attribute of Value type (that can accept 
> both specialized types).
>
> Thanks