variable hierarchies

[Anon]

Hi there!

How do I organize hierarchies of data (somewhat like threading in a discussion forum), however retaining the flexibility to change the order of the items, moving them within a level of the hierarchy or between different levels (taking along the items that are below this level, belonging to the level to be moved).

Basically: How do I make things stay in a different order and make it EASY to change the order including subitems?

Thanks a lot!

Ben

[terje-s]

Well, I don't have an example of how to do it, basically because I havn't. My guess, however, would be to use some sort of parent field for each entry.

E.g.:

CREATE TABLE thing (
id int(11) default '0' not null auto_increment,
parent int(11) default '0' not null,
info text,
primary key (id)
);

then, you'd insert some records;

'', '0', 'sometext'
'', '0', 'moretext'
'', '1', 'testtext'
'', '2', 'uglytext'

and so on. Then, use some sort of function to display all entries with parent=0, then display all childrens for those entries, then all children for those children etc etc.

By changing the parent of one entry, it should theoretically move that one with all children to somewhere else. (The 'parent' field would ofcourse contain the 'id' of another entry).

[Anon]

Thanks for the comment! However, this is only part of what I wanted to know. How do I put the children in a specific order and how do I change this order in a simple way?

Thanks again.

Ben