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 > > > > >