[thelist] Interesting SQL Puzzle
Frank
lists at frankmarion.com
Sat Aug 20 10:11:51 CDT 2005
I've got a situation where I have 100 records. Each record has a field
named "rank" whose numeric value represents the record's position in a
list. If the user wants to move a record to a different location on the
list, s/he can change it.
My puzzle is this: a user enters a 101st record and wants it to be located
as item 33 in the list, thus, record with the current value of 33 would
be updated to #34, and so on down the line. If a record is deleted, all
the higher valued records would have to be re-updated.
(Tangent: if sorting by rank. the last statement is not necessarily true,
36 is still higher than 34, but I can see potential issues arising if it's
not kept tight)
How do I go about re-ordering the records to prevent collision? Seems to me
that updating 64 records with a different rank might be rather inefficient,
especially if we have a lot of records.
Can anyone suggest a different method?
Frank Marion lists at frankmarion.com Keep the signal high.
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