OpenEuphoria

Re: onKeyPress()

• Posted by George Walters <gwalters at sc.rr.com> Aug 06, 2001
• 481 views

OK, that's a lot more than I probably needed to know..I certainly got the
wrong idea in my head somehow...So we shoudn't have to worry about changing
tables or DB's...

thanks Rob

...george


----- Original Message -----
From: "Robert Craig" <rds at RapidEuphoria.com>
To: "EUforum" <EUforum at topica.com>
Subject: Re: onKeyPress()


>
> George Walters writes:
> > I read from Rob's response that changing
> > tables does in fact scan the entire file
> > pulling 4 bites from each record...
>
> EDS does not scan the entire file, or
> even the entire table.
>
> If your table has 1000 records (of any size),
> db_select_table() will read in 1000 pointers
> to those records on disk. This is 4000 bytes
> of data split into a number of contiguous blocks.
> EDS tries to maintain, very roughly, sqrt(number of records)
> pointers per block, e.g. roughly 32 blocks of 32 pointers (128 bytes)
> per block, but it can vary a lot, depending on deletions etc.
> EDS seeks directly to the start of each block and starts
> reading it. There is no "scanning" or searching of the file.
>
> I doubt that this is going to slow you down enough
> for the user of your program to notice. It might be
> a problem if you are doing a massive operation
> over the whole database, selecting tables millions of times.
>
> Regards,
>    Rob Craig
>    Rapid Deployment Software
>    http://www.RapidEuphoria.com
>
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