> From: Kevin Windham <[EMAIL PROTECTED]>
> Date: Thu, 2 Mar 2006 11:17:15 -0600
>
> On Mar 2, 2006, at 10:44 AM, Trausti Thor Johannsson wrote:
Hi Trausti,
Hi Kevin,
>> Just out of curiosity, and to learn. I have seen some mails here
>> about databases containing like 30 million or more records. I have
>> never worked with a database like that. The largest table I have
>> is like 90.000 records. So my question is, how does one work with
>> such a database without doing things like I do them currently.
>> Currently, I have an Object that takes an sql command, queries, and
>> then read all into a dictionary containing individual objects.
>> 90.000 records, it does take time to read on, and create objects.
This is danger actually. And this break rules of database usage.
Besides, so you load all your data into RAM dictionary.
Then what you do next?
Only read them?
Do searches? By exact value only?
Sorting?
Modifications?
All these operations in fact are DBMS kind operations.
>> I would think that reading in the whole shebang would cause out of
>> memory or something bad happening, having millions of objects in
>> memory. At least it would take an awful long time.
Of course. Rule of work with some database and especially with some DB
Server is: touch as minimum records as you can. Unlock records as fast as
you can. Respect other users of this database.
>> Hope someone can help me with this one. I do not care how some
>> databases do this, I have heard very nice things about valentina
>> database, but I am asking as a more formal computer science approach.
>
> I can give you one method. It would be similar to what WebObjects
> does. What you would do is use a server side cursor if available on
> your DB server. If not you could fudge your own. Essentially you
Kevin have point you server side cursors, although I have not yet see if tou
use local or remote database. Trausti, before help you it needs more details
about your task.
If you want you can subscribe to Valentina list to discuss your
database-related task there. Never mind if you use other db.
--
Best regards,
Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc
Valentina - Joining Worlds of Information
http://www.paradigmasoft.com
[I feel the need: the need for speed]
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