-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Gary Poster wrote: > On Nov 17, 2006, at 10:23 AM, Adam Groszer wrote: > >> Hello, >> >> Solutions: >> >> a: No, do not keep None values in the catalog >> the current implementation works like this >> you are unable to ask the catalog for objects having None >> properties >> b: Yes, keep None values in the catalog >> you can ask the catalog for objects having None properties >> c: Let's keep the existing one that does not index None and have an >> AttributeIndexAlsoNone class which will index None values > > Did you see my reply in the other thread? > > If you make indexes keep track of None, it will need to be done in a > separate data structure because of the key homogeneity issues. This > is a less efficient approach than the zc.catalog approach. It can be > done either way. > > I recommend that you use zc.catalog, rather than reinventing > something that solves your problem. > > I suppose I don't care much, since we don't use the standard zope > value and keyword indexes anyway; if you must add the None feature, > then I only care, from a "let's not screw up our community software" > perspective, that it be implemented in a safe way. Keep your BTree > keys homogenous.
I don't get this -- an OOBTree promises to index *objects* as keys; None *does* behave properly as a key when mixed with strings. You can't count on it sorting in a particular way, but it *is* consistent. Worrying about consistency across, e.g., a major Python version upgrade (the only thing which I can envision changing the partial ordering) doesn't justify throwing out 'None' as a legitimate indexable value in all cases. In general, I don't think the storage mechanism should dictate the *policy* choice, which is whether 'None' is a "meaningful" value for the index. In many cases, having 'None' as the value for an attribute is *not* the same thing as not having the attribute at all -- I'll agree with you that objects who don't have the attribute should not Tres. - -- =================================================================== Tres Seaver +1 202-558-7113 [EMAIL PROTECTED] Palladion Software "Excellence by Design" http://palladion.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFFXgOb+gerLs4ltQ4RAqnYAJ9r/o4E5ptIHeW29rlDcj97qeabUACfe8yr 8T2gWGEpmkXGEb07qEq/hFQ= =IHm7 -----END PGP SIGNATURE----- _______________________________________________ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
