Posted by Tom Fulton on October 20, 2005 at 11:28:32:
In Reply to: Re: A Multi-Keyed File Usage Tip -- not true! posted by Jim Guerber on October 20, 2005 at 07:34:25:
Hi All,
I've just been pondering on the documentation of the multi-keyed files and would like to ask a question on Key Order. In order to establish
unique keys in the SubKey files the documentation states that you use
"their position in the data file". I'm not sure what the nature of the
position is ( a numeric counter or a memory address? ). Did you consider using the primary key as the additional piece of information that makes the subkey unique? As an example, we have an item file of
colorways each of which must have a valid pattern #, patterns being kept in a separate file. So if items 0089-01, 0089-02 and 0089-03 all
have pattern 0089 then a listing program of items by pattern running off the subkey file could list as
Item SubKey
0089-02 0089 + position in file
0089-01 0089 + position in file
0089-03 0089 + position in file
depending on the order they were input, deletions, etc., whereas if the primary key was used to make unique then you'd get
0089-01 0089 + 0089-01
0089-02 0089 + 0089-02
0089-03 0089 + 0089-03
Tom.