Hi Pete, Thank you for theinformation.
Yes, that was driving me crazy, I would have been entered on the patients' list but with a mental problem. Thanks to php_mysql group, the list will remain 2000 long :) Best regards to all David --- Pete <[EMAIL PROTECTED]> wrote: --------------------------------- In message <[EMAIL PROTECTED]>, David Halliday <[EMAIL PROTECTED]> writes >Hello Dave, >Sorry about this delay but i wasnt feeling well >yesterday. Presume your name is now in your own database, then? <G> >Just two remaining points .. I think that MYSQL tables >can have a maximum of about 65000 rows and about 3400 >columns. Now in this particular case .. in theory >only .. 2000 patients could be on 70 drugs each .. >hence the in third table "patient_med", we would have >70 X 2000 = 140,000 rows. You must have some sick patients! All of them taking 70 different medications??? The size limit is a mixture of rows and columns - a table with more columns can have less rows - but the table must be less then 4Gig in size for MySQL V3.22. For V3.23+, the maximum size is 65536 terabytes, which means the limit will be down to your operating system. Your patient_med will only need 2 fields, so I can't see it being an issue. And I wouldn't expect you to need more than about 10,000 rows in that table. Guessing... You could figure it out exactly by adding together all the rows in your 70 tables. >And a point about speed, on average .. how long would > it take to check 65000 rows in this case .. >obviously it depends on several factors. I am thinking >really about ways of optimising the script and making >it faster. Make sure that, the Patients and Medicines tables are indexed on the key that you will use within patient_med table. You won't see any delay on such a simple search. -- Pete Clark http://www.hotcosta.com http://www.spanishholidaybookings.com ___________________________________________________________ To help you stay safe and secure online, we've developed the all new Yahoo! Security Centre. http://uk.security.yahoo.com ------------------------ Yahoo! Groups Sponsor --------------------~--> Get Bzzzy! (real tools to help you find a job). Welcome to the Sweet Life. http://us.click.yahoo.com/A77XvD/vlQLAA/TtwFAA/CefplB/TM --------------------------------------------------------------------~-> The php_mysql group is dedicated to learn more about the PHP/MySQL web database possibilities through group learning. Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/php_mysql/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
