Hi Thomas, Sounds like a much cleverer solution. I'm not sure what you mean by an associative hash or how I would create it and test the serial numbers against it. I know a little about using hash functions in cryptography and signing but only in very basic terms.
I don't run both queries for every label, it depends on which part is being printed. There are a couple of dozen different parts that can be produced by the app. Thanks, Dave. Dave Murray Delphi-En Moderator Glasgow, UK [EMAIL PROTECTED] --- In [email protected], Thomas Hruska <[EMAIL PROTECTED]> wrote: > > > I see your problem. You take a linear logical approach to reach a > working solution. It won't matter what DB you use if you use such > and approach - performance will suck. What you should do is > generate a list of 1000 serial numbers and store them in an array > AND associative hash. > You can make sure the list is unique by checking each new serial > number generated against those in the associative hash. Then, run > the first SQL query. For each row in the query, check the > associative hash to see if the serial number already exists. If it > does, locate it in the array and flag it as not being unique. > Repeat for the second query. > > Once the two queries have been processed, the array contains a > unique set of serial numbers to both itself and the database. Run a > batch insert to add the serial numbers to the 'LOG' table __BUT__ > flag them as having not been used. This allows you to have two > programs: One that generates valid serial numbers and one that > prints the labels. > > If you use the two program approach, the program that prints the > labels simply has to run the appropriate SQL query for _unused_ > serial numbers, run an UPDATE query to flag it as used, and then > print the serial number. > > One way to further improve performance with this approach would be > to remove the 'order by' and introduce a surrogate primary key using > an 'autonumber'. A 32-bit integer outperforms ASCII string > comparisons any day. > > -- > Thomas Hruska > CubicleSoft President > Ph: 517-803-4197 > > Safe C++ Design Principles (First Edition) > Learn how to write memory leak-free, secure, > portable, and user-friendly software. > > Learn more and view a sample chapter: > http://www.CubicleSoft.com/SafeCPPDesign/ > ----------------------------------------------------- Home page: http://groups.yahoo.com/group/delphi-en/ To unsubscribe: [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/delphi-en/ <*> 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/
