Hi Henrik,
> of a heavier web framework than pl-web and for the read part I need to
> be able to walk through all objects of a certain type regardless of
> what kind of keys and references they might or might not have.
> ...
> (dbs
> (4 +User) #1
> ...
> (dm read> ()
> (let Cur (car (get This 'Dbf))
> (make
> (while (setq Cur (seq Cur))
> (link Cur) ) ) ) )
OK, you are on the right track. 'seq' is the way to access all objects
in a given file independent from indexes and references.
I always use the following pattern in such cases:
(for (This (seq (db: +User)) This (seq This))
(when (isa '+User This)
(doSomething This) ) )
> The above works but not for +User (I assume because they are in the
> first file), trying (read> '+User) will still return some relations.
Right. The reason is that the first DB file contains also other,
non-entity objects holding meta informations. Most notably the root
object (in '*DB')
> {1} NIL
> +Menu {7}
> +Block {6}
> +Page {5}
> +User {3}
and also the the bases of indexes like
> {5} NIL
> parent (5 . {G3})
> path (6 . {G2})
> name (6 . {G1})
> Of course I could filter them but there must be a better/more
> efficient way?
A filter is necessary here. But I would not worry, a simple 'isa' as in
my example above won't introduce a noticeable overhead.
(dbs
...
(3 (+Page name path parent)) #8
...
> (rel name (+Ref +String))
> (rel path (+Key +String))
> (rel parent (+Ref +Link) NIL (+Page))
>
> I would have expected those refs and key to end up in file #8?
Correct. But while the _nodes_ of those index trees do indeed reside in
#8, the _base_ still is in an external symbol in #1.
Cheers,
- Alex
--
UNSUBSCRIBE: mailto:[email protected]?subject=Unsubscribe
