Thread: period data type

period data type

From
Warren Turkal
Date:
Hello,

Is anyone working on a period data type as described in Dr. Richard Snodgrass' 
book _Developing Time-Oriented Database Applications in SQL_[1]? I did not 
see a relevant project listed in the TODO. I would like to contribute 
(possible funding and/or coding) the development of a conforming 
implementation of this data type.

[1]http://www.cs.arizona.edu/~rts/tdbbook.pdf

Thanks,
wt
-- 
Warren Turkal (w00t)


Re: period data type

From
Michael Glaesemann
Date:
On Feb 5, 2007, at 12:47 , Warren Turkal wrote:

> Is anyone working on a period data type as described in Dr. Richard  
> Snodgrass'
> book _Developing Time-Oriented Database Applications in SQL_[1]? I  
> did not
> see a relevant project listed in the TODO. I would like to contribute
> (possible funding and/or coding) the development of a conforming
> implementation of this data type.
>
> [1]http://www.cs.arizona.edu/~rts/tdbbook.pdf


This is an area I'm actively working on. I've worked out an example  
using composite types and PL/pgsql, though it's not very performant.  
I'm currently looking at making a contrib module, but have been  
slowed a bit by my lack of C experience. Regarding conformance, as  
there's currently no standard, I'm leary of cleaving too closely to  
the Temporal SQL proposal to ward of making something that would be  
close but not quite conformant to a future addition to the SQL  
standard. Also, I hope to make a more general interval/range/period  
constructor that would allow you to make "periods" of other types  
(say, integers) as well. I've found Date/Darwen/Lorentzos' Temporal  
Data and the Relational Model[1] very helpful.

Interested in possibly working together?

Michael Glaesemann
grzm seespotcode net

[1]http://books.elsevier.com/uk/mk/uk/subindex.asp?isbn=9781558608559