[daisy] Daisy Questions

[Steven Noels]

On 23 Sep 2006, at 02:14, Paul VanWechel wrote:

> Thanks for the very helpful answers. I apologize for the long delay  
> in response - I had a family emergency that forced me to leave the  
> country temporarily - I just returned earlier this week. For other  
> reasons, the project was delayed until Q1 next year anyway.

Thanks for coming back, I hope all turned out well.

> I talked with the team member that had been given the scalability  
> quote - and it turns out they were eliminated from the selection  
> process anyway. Despite not being fond of their sales team, we  
> would prefer to not mention their company name. :)

Oh well. :)

> One additional question, from another person on our team:
>
> When defining a form and a set of fields we are not always sure  
> which forms will have lots of data several months later. Since  
> Daisy stores all field values in one table, we were unsure if there  
> was a mechanism for transparently moving a group of fields out of  
> this table into a separate schema table in the same database,  
> without any changes to references in previously defined queries in  
> the daisy query language. A form may have thousands of instances  
> and for performance reasons it seems necessary to occasionally make  
> these changes to the schema. If this is not possible, can we define  
> a separate schema table ahead of time when we anticipate a large  
> amount of data, and refer to the fields/columns as if they were  
> 'normal daisy fields' in the query language(?).

Our general idea about performance optimalisation is to not fix what  
isn't broke. We know that the sparse fields table can grow rapidly,  
but it gave us the benefit of having a fixed database scheme to start  
with. Plus databases are designed to work with such tables rapidly  
and scalable. Given a real requirement and a real business case, we  
can determine the need for optimalisation and act upon that.  
Pragmatically thinking, if one is planning to use Daisy for an  
enterprise environment, we can safely assume that there's been given  
some thought about development to support such environments. The  
import/export tools BTW also came into existence due to a customer  
requiring such a tool to support his business case.

</Steven>
-- 
Steven Noels                            http://outerthought.org/
Outerthought                              Open Source Java & XML
stevenn at outerthought.org                stevenn at apache.org