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From:Mogens Melander Date:June 19 2007 1:42pm
Subject:Re: Storing a linked list
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How about:

$id1 = 1;
$id2 = 0;

while ($id1) /** or ($id2 != 8) **/
{
	$sql = "select * from table where id1=$id1";
	$row=query($sql);

	$id1=$row->id1;
	$id2=$row->id2;

	do_stuff();

	$id1 = $id2
}


On Tue, June 19, 2007 10:58, Matt Juszczak wrote:
> Hi all,
>
> I've got a table such as the following:
>
> id1 char
> id2 char
>
> sample data looks like this:
>
> id1	id2
> 1	3
> 2	4
> 3	5
> 5	6
> 6	8
>
> And of course another table has something like:
>
> id	info1	info2	info3
> 1	blah	blah	blah
> 2	blah	blah	blah
>
> I'd like to store paths to specific destinations...
>
> In other words, the path from 1 to 8 is:
>
> 1,3,5,6,8
>
> I was thinking of creating a table called relationships
>
> start	end	path
> 1	8	{3,5,6}
>
> This would allow me to easily display the path if I know the start and
> end, but
> what it doesn't allow me to do is reuse the data.
>
> IE: say that I calculate the path from 1 to 8 as 1,3,5,6,8, and then I
> want to
> know the path from 3 to 6.  even though this is already calculated, I have
> to
> recalculate it as another row... hence
>
> start	end	path
> 1	8	{3,5,6}
> 3	6	{5}
>
> I considered making another table, called hops, such as:
>
> start	end	relationshipID
> 1	8	1
>
>
> table hops:
> relationshipID	start	end
> 1		1	3
> 1		3	5
> 1		5	6
> 1		6	8
>
> Then I could almost "reuse" those hops somehow.... but not sure.
>
> Can anyone recommend a good way to store this data?
>
> Thanks!
>
> -Matt
>
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-- 
Later

Mogens Melander
+45 40 85 71 38
+66 870 133 224



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Thread
Storing a linked listMatt Juszczak19 Jun
  • Re: Storing a linked listMogens Melander19 Jun
  • Re: Storing a linked listPeter Brawley19 Jun
    • Re: Storing a linked listBaron Schwartz19 Jun