Re: SQL, Logical Files, Unions & Indexes.

["Caura" <caura@xxxxxxxxxxxxxxxx>]

Hi,

a query via Hibernate on one region takes multiple seconds - not subsecond 
as our classic application.

I will try to live with this, but the problem is that a Union is a View .
And one cannot create Joins over 2 or more Views, can you?

<quote from my previous post>
... a general library is defined that contains all the necessary logical
files, with the same name as the logicals in each regional library,
and these general logical files point "overall" to all the physical files
are tables of all the region libraries.
So,via a simple librarylist switch, all overall data are accessible for the
central site (control)-people,
with exactly the same programs as used in the regions, and this as well for
online direct access, as for general statistics work, as for any other
process  .
</quote>

As long as we cannot create Joins over our "overall-logical-files" or either 
"SQL-unions" for that matter,
a same setup ("region" vs "overall data", based on librarylist/ Relational 
Database) cannot be accomplished.

I hope I'm totally wrong.
luc


----- Original Message ----- 
From: "Alan Campin" <Alan.Campin@xxxxxxxxxxxxxxxx>
To: <midrange-l@xxxxxxxxxxxx>
Sent: Tuesday, April 03, 2007 1:25 AM
Subject: Re: SQL, Logical Files, Unions & Indexes.


> <snip>
> 1) I can replace our 'overall-logcal files'  with SQL Views, but I
> cannot
> create an index over multiple tables (as I can via a logical file),
> so these views will not give me the sub-second accesstimes I have now
> (or am
> I wrong in this?)
> 2) Hibernate creates "joins" over multiple tables under the covers, but
> -as
> far as I know- this cannot be done on the current "overall-logcial
> files",
> or on any alternative using  "union"- views (I hope I am wrong on this
> one
> too) ?
> </snip>
>
> I am not sure this answers the question. The question was if you run
> this over one region using SQL, how long does it take to return the
> result set and how big is the result set?
>
> For example, if it takes 30 minutes to query one region and it returns a
> 100,000 records, union might not be practical.
>
> If it takes a second to run and returns a single result set, unions
> should work fine.
>
> Based on what you are saying, you would like to run this from a PC
> application. Why not build the result in a stored procedure and return
> to caller or am I missing something?
>
>
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