Re: ADQL WD v1.05

From: Ed Shaya <eshaya-at-umd.edu>
Date: Fri, 07 Jul 2006 10:12:32 -0400

Jeff Lusted wrote:
> Yuji SHIRASAKI wrote:
> 

>>
>>> (1) ADQL/x and ADQL/s.
>>>
>>> There are now two ways of specifying ADQL: BNF and XML schema. 
>>> Although you state "ADQL/s and ADQL/x are translatable to each other 
>>> without loss of information", does this apply to the specifications 
>>> themselves? 
>>
>>
>> Yes.
>>

>
> I'm glad we agree that the ADQL schema and the BNF definition of adql
> should be equivalent. This is very important to our work on query
> building in Astrogrid. However, I find your view difficult to reconcile
> with ...
>

If I remember the history of this correctly, Wil originally did a direct   translation from BNF of SQL to XML to create the first ADQL.xsd. However, there was a major rebellion because the resulting schema was unbearably complicated. As a result Wil made major adjustments to simplify ADQL. Therefore, the present ADQL does not faithfully reproduce the BNF. Isn't that the story?

Ed Received on 2006-07-07Z16:30:24