Hello,
I'm developing a system (with PHP-MySQL) in which I will have different
articles published. Any given article can correspond to a category (or
sub-category (or sub-sub-category)). Something like this:
Cat 1
Sub 1.1
Sub-Sub 1.1.1
Sub-Sub 1.1.2
Sub 1.2
Sub 1.3
Cat 2
Sub 2.1
Sub 2.2
Sub-Sub 2.2.1
Sub-Sub 2.2.2
[etc]
As per my research on this topic of publishing 'treelike information', there
are two posibilities:
a) Adjacency list
id | parent | label
1 0 Cat 1
2 1 Sub 1.1
3 2 Sub 1.1.1
[so on...]
b) Nested sets (as explained in the book JOE CELKO'S SQL FOR SMARTIES
(Morgan-Kaufmann, 1999, second edition), that I don't have...)
label | lft | rgt
Cat 1 1 12
Sub 1.1 2 7
Sub 1.1.1 3 4
Sub 1.1.2 5 6
Sub 1.2 8 9
Sub 1.3 10 11
[so on...]
Anybody is doing something like this that can share experience with us? I
can not find a clue yet if one system is better than the other for what I
need. I realized that the 'Nested Sets' system have a very good approach and
is very easy to get all the sub (and sub-sub) categories on a given category
(any record where lft is between lft and rgt:
SELECT e1.*
FROM example as e1, example as e2
WHERE e1.lft BETWEEN e2.lft AND e2.rgt
AND e2.label = 'Cat 1';
)
But I'm having problems trying to find -as example- which are all the
Categories (in the other system are all the records where parent = 0)...
Any ideas?
Regards,
Tomas Garcia Ferrari
Bigital
http://bigital.com
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