Posted by Tom Fulton on October 24, 2005 at 13:23:58:
In Reply to: Sub Keys are NOT unique posted by Jim Guerber on October 23, 2005 at 09:36:54:
This thought occurred after a discussion with Steve Hagen. We were discussing the issue of the primary key being the "behind the scenes"
field that keeps the sub-key pointing to only one key in the primary file. Not having read the documentation, Steve said "... in the sub-key file you'll have a key of name plus customer number...". I started to
say, "But it doesn't quite work that way" when I thought why not?
Many of our keyed-only pointer files are made up of multiple-field keys.
Why not pick an arbitrary number of fields, say five or six, and have the ability to specify the starting position and length five or six times? This information would be stored by Comet in the file header info. It would eliminate the need for the primary key to be behind the scenes because it could be specified as one of the key parts. The total length would have to be below some maximum. The concept would be exactly the same as the KEYCHEK utility where you input the starting position and length for verifying key against record. File problems on a sub-key file??? A utility could rebuild as long as it could read the header to grab the multiple pos & lengths. Lots of possibilities here if I'm driving down the right road. Of course I may be using Vermont road maps and driving in California. Tom.