Limiting cursor size

[Ruslan Zasukhin]

on 6/13/03 3:02, Chris Kelly at c.kelly at qfsaustralia.com.au wrote:

Hi Chris,

> I believe Mysql  just uses the keyword LIMIT
> 
> If this was something you were considering Ruslan , would you also
> think about being able to define a starting offset for the cursor?

Yes we going to add this feature.

As always we want

1) follow SQL Standard
2) may be optionally provide popular syntax, e.g. From mySQL.


> So if you were dealing with large volumes of data you could use LIMIT
> and supply an offset as well for the data ,   so in effect  you were
> just obtaining  the next N rows of data in the cursor from the offset ?
> 
> I know this is  used this extensively with php and mysql.

Do you know why this is  used this extensively with php and mysql ?

Because mySQL have only client-based cursors.
So you MUST to have way to say: I want records from 10 to 20.

In Postgre for example, cursor is server-based,
So after query all data are on server,
You later do Fetch from 10 to 20 and that records go to you.


Valentina have both -- client and server cursors.
So LIMIT is not so critical.
But it really have sense because in some cases it can improve speed of query
Reducing amount of work for database.

-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
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e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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