As far as I know, the key location makes no difference, however, the sort items should be placed at the bottom of the set because of "extended sort" (when two sort keys are identical, Image uses the fields after the sort key to do an "extended sort").
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>>> Jim Phillips <[log in to unmask]> Tuesday, December 20, 2005 8:41:05 AM >>>
I was just adding a new detail data set to an existing
Image data base and the following question occurred to
me: Does it make any difference in terms of I/O speed
or efficiency where the search items (key fields) are
located in the data set?
Traditionally, the data sets I have seen have all the
search items at the beginning of the data set:
Key-Item1 (Key1-Master)
Key-Item2 (Key2-Master)
Data-Item1
Data-Item2
...
Data-ItemN
Now is this just convention or is it because it is
"better" (and define "better")?
I mean, couldn't you layout a detail data set like
this:
Data-Item1
Data-Item2
Key-Item1 (Key1-Master)
Data-Item3
...
Key-Item2 (Key2-Master)
...
Data-ItemN
Would there be any adverse effects from such a data
structure?
Inquiring minds want to know...
Jim Phillips
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