Re: CUSTOM ORDERING IDEA
Re: CUSTOM ORDERING IDEA
- Subject: Re: CUSTOM ORDERING IDEA
- From: Robert Walker <email@hidden>
- Date: Thu, 27 Apr 2006 10:24:24 -0400
Amedeo,
I think we may need bit more background here. If you are talking
about the order that the database engine inserts records onto the
physical disk then that would be very impractical. Typically
databases insert new records at the end. If they were to insert
records somewhere in the middle they would have to move all the
records that follow the insertion. Obviously this is not what you're
talking about.
So you must be referring to using an indexed column to provide a sort
ordering. One case that comes to mind, is that I had a customer who
wanted to keep line items on an order in the same order they were
entered into the system. Viewing an order later needed to show line
items in the same order. The solution for this was to add an integer
column to the line item (visible to the user). Then a routine was
added to maintain this ordering during save. The routine was
responsible for generating the next number on an appended item, and
reordering the line numbers on an insert or delete.
If you are talking about keeping a custom ordering for an entire
table that could be a real performance nightmare causing you to have
to update a lot of rows each time a record is inserted (this would
only be plausible if your table has just a few rows). I've used
something similar to this for enumerated strings that I wanted to
keep in a particular order in the database. I used a similar
approach as above to support this. Again this table had only a few
rows, not more than 20 in my case. Plus this only had to be
maintained on a very occasional bases.
On Apr 27, 2006, at 9:34 AM, Amedeo Mantica wrote:
Hello friends!
does anyone have an idea how to implement a custom row ordering in
a database?
My customers want to custom order row in database
i can create an ordering column with a double type (number) so i
can always move a row between two others...
Actually I don't know how to graphically impement this (user
interface)
do you have ideas? or other methods?
Thanks
Amedeo
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