Re: How is it done?
This WebDNA talk-list message is from 1998
It keeps the original formatting.
numero = 17443
interpreted = N
texte = >>When a search includes several different values to be checked in a single >>database field, how is the search performed? >> >>Is the database traversed once from top to botton for each value (thus >>moving from top to bottom several times), or is each record checked for >>all the values before moving to the next record (thus traversing the db >>from top to bottom just once)? > >The internals of how a search is performed are private and even changed >from release to release in favor of better/faster algorithms. Right now it >is probably visiting each record once before moving on, although sorting >can visit records in an apparently random pattern. Is there some >noticeable side-effect you are seeing?Searching records with multiple values seems to be taking a very long time. I know that part of the problem is because it's a 250,000 record database and I'm running on a 68040 Mac, but the slowness of this search almost demands that I create an entirely new field in the db and enter specially-customized values into that field just so I can get rid of the multiple parameters and search on a single parameter in a single field instead.The only problem with this approach is that:1- It makes the db even larger than it already is, and ... 2- The data comes from someone else's UNIX db and it's hard enough to parse and format as it is. Plus, the data is updated weekly, so i'm not sure my proposed solution is going to work as a long term solution even if I did use my approach ...Sincerely, Ken Grome 808-737-6499 WebDNA Solutions mailto:ken@webdna.net http://www.webdna.net
Associated Messages, from the most recent to the oldest:
>>When a search includes several different values to be checked in a single >>database field, how is the search performed? >> >>Is the database traversed once from top to botton for each value (thus >>moving from top to bottom several times), or is each record checked for >>all the values before moving to the next record (thus traversing the db >>from top to bottom just once)? > >The internals of how a search is performed are private and even changed >from release to release in favor of better/faster algorithms. Right now it >is probably visiting each record once before moving on, although sorting >can visit records in an apparently random pattern. Is there some >noticeable side-effect you are seeing?Searching records with multiple values seems to be taking a very long time. I know that part of the problem is because it's a 250,000 record database and I'm running on a 68040 Mac, but the slowness of this search almost demands that I create an entirely new field in the db and enter specially-customized values into that field just so I can get rid of the multiple parameters and search on a single parameter in a single field instead.The only problem with this approach is that:1- It makes the db even larger than it already is, and ... 2- The data comes from someone else's UNIX db and it's hard enough to parse and format as it is. Plus, the data is updated weekly, so i'm not sure my proposed solution is going to work as a long term solution even if I did use my approach ...Sincerely, Ken Grome 808-737-6499 WebDNA Solutions mailto:ken@webdna.net http://www.webdna.net
Kenneth Grome
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