I'm not sure offhand. Different stores will have different low-level
access to the data structure. Robert might be able to do this via a
SQL query. Not sure about Henrik's Postmodern implementation.
This probably isn't possible for the BDB data store. You can get the
leaf count for a BDB Btree, but not for a subtree (we multiplex
Elephant BTrees on a single, large BDB BTree).
Perhaps we could provide a mixin class that automatically maintains
this count on the lisp side for a user subclass of persistent-
collection?
Ian
On Oct 2, 2007, at 10:34 AM, Mariano Montone wrote:
Hello,
I would like to know which is the best way to get the size
of a persistent-collection (for example the number of instances of
some class). I haven't be able to find a method. And uploading all
the objects to memory to count them is not an option.
Cheers, Mariano
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