Question

I would like my client to be able to order items in the backend. I figured the easiest way to do it is to have the database table for an item have a field called “order” which gets a value. This is a value the client puts in. Then I can just run SQL queries ordering by the “order” field.

Right now I have it very simple.. there is no logic.. so the user would put in order=100 for one item and order=200 for another.. and the one with the lower value would get listed first. Is there a more elegant way of doing this? I am thinking of something like “move up” and “move down”. etc. I am trying to make administrating items more convenient.

Any ideas would be greatly appreciated!

Answer 1

As far as the database goes, your solution using an order field is correct. You probably don’t want to expose this to the user though, and using a pair of up- and down arrows the text input can be circumvented. When a user clicks the ‘up’ arrow, you basically switch the specific record with the record above it. In meta-language:

// $myId holds id of record, $myOrder holds the order of the record

SELECT id, order FROM t WHERE order < $myOrder LIMIT 1
// Store id in $nextId, order in $nextOrder

UPDATE t SET order = $nextOrder WHERE id = $myId
UPDATE t SET order = $myOrder WHERE id = $nextId

Note that this is only a very rough draft, you will have to add proper escaping. Also, if you want a UNIQUE index on order to ensure a strict ordering, you will need to change the last two statements.