Move Up/Move Down Tutorial and/or Help?

localscene

I need some help with a script, the problem is I'm not sure where to even start on it...

I want to write a script that will allow me to move the order of links on my Web site. The links are stored in a MySQL database.

So for example, I want to take a list of links as such:

Apple Link (MOVE UP / MOVE DOWN)
Potato Link (MOVE UP / MOVE DOWN)
Orange Link (MOVE UP / MOVE DOWN)
Pickle Link (MOVE UP / MOVE DOWN)

And change the order at will. For example to:

Potato Link (MOVE UP / MOVE DOWN)
Orange Link (MOVE UP / MOVE DOWN)
Apple Link (MOVE UP / MOVE DOWN)
Pickle Link (MOVE UP / MOVE DOWN)

And to be able to continue to change the order of new links added to the database in the future.

I looked at the code in phpbb that allows one to change the order of forums (MOVE UP/MOVE DOWN), but the code is lumped in with a lot of other stuff and is massively confusing.

Is anyone aware of a good tutorial to learn to do this or sample code?

Thanks

void_function

First, add a field in your tables, like link_order, and if your tables are already filled, write some simple script that will set a sequence from 1 to n.

Second, when you query your links, order them by this link_order, DESC or ASC depending on what you want.

Make the MOVE UP link to point at, for example, move.php?id=$lid&dir=up, where $lid is the primary key of the link.

In move.php fetch id and dir variables, and use code not unlike this one:

$res= myqsl_query ("SELECT link_order FROM table WHERE id=$id LIMIT 1");
$old_order= mysql_result ($res, 0);
if ($dir=="up") $new_order= $old_order -1;
else $new_order= $old_order+1;

// Now swap the two links' positions:
$res= mysql_query ("SELECT id FROM table WHERE link_order=$new_order LIMIT 1");
$nid= mysql_result ($res, 0);
$res= mysql_query ("UPDATE table SET link_order=$old_order WHERE id=$nid LIMIT 1");
$res= mysql_query ("UPDATE table SET link_order=$new_order WHERE id=$id LIMIT 1");

Note that his is extremely basic example code and you need failsafe mechanisms, like checking if moving up has reached top. Likewise for moving down. Then if the input values are correct, etc... You migtht also wish to set an index to link_order

localscene

void_function wrote:
First, add a field in your tables, like link_order, and if your tables are already filled, write some simple script that will set a sequence from 1 to n.

Second, when you query your links, order them by this link_order, DESC or ASC depending on what you want.

Make the MOVE UP link to point at, for example, move.php?id=$lid&dir=up, where $lid is the primary key of the link.

In move.php fetch id and dir variables, and use code not unlike this one:
$res= myqsl_query ("SELECT link_order FROM table WHERE id=$id LIMIT 1");
$old_order= mysql_result ($res, 0);
if ($dir=="up") $new_order= $old_order -1;
else $new_order= $old_order+1;

// Now swap the two links' positions:
$res= mysql_query ("SELECT id FROM table WHERE link_order=$new_order LIMIT 1");
$nid= mysql_result ($res, 0);
$res= mysql_query ("UPDATE table SET link_order=$old_order WHERE id=$nid LIMIT 1");
$res= mysql_query ("UPDATE table SET link_order=$new_order WHERE id=$id LIMIT 1");
Note that his is extremely basic example code and you need failsafe mechanisms, like checking if moving up has reached top. Likewise for moving down. Then if the input values are correct, etc... You migtht also wish to set an index to link_order

Thanks for the help. This should help me get started.