Re: Type inheritance

Oh that was just an example...Let me make a real example:
I have a table "Sensors" (that has to contain different sensor types) with
a Value. That value doesn't have to be fixed, but I want to define it in a
way that it changes its structure when the sensor type changes. For
example, for Temperature sensor I would like to have just a float number,
but for the humidity I could need of absolute and relative humidity
(2 floats). I'd just like to know if I can say that the VALUE is a composite
type...that I have then to specialize in Temp Type and Humidity type...using
them in their particular case.

This procedure has a name...and it's the inheritance. As I understood,
postgres allow me the table inheritance, but not the type inerithance. Here
is an example about how this works on Oracle:
http://www.oracle.com/technology/products/oracle9i/daily/jan29.html
2009/6/5 Rob Sargent <robjsargent(at)gmail(dot)com>

> 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
>>
>
>
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