--On 23. April 2006 14:57:52 -0400 Pete Taylor <[EMAIL PROTECTED]> wrote:

hmmm...  i don't guess i disagree with those contentions directly, as
they apply to sql.  but i do think that a query language of some kind
for the zodb would be beneficial.  i have already encounted user-realm
questions on applications i've built that would be more easily
answered with a query language, rather than specific python scripts or
catalogs.  the trouble with catalogs is that until you know you're
going to want to index on and query certain information, you probably
won't build an index for it in the catalog...  and it's a non-trivial
amount of work to make querying the zodb, even with hurry.query, work
the right way.

In reality you don't want to search inside a RDBMS for unindexed data
for performance reasons. This is even more true for Zope since you have to read all data of the ZODB..this will be totally inefficient especially
for large installations. Zope object can be very complex: attributes can be
basic Python types, Zope BTrees, hierarchial data etc...how will you define
a query language that covers all use cases? In Zope 2 we have something like AdvancedQuery to specify almost generic queries for the ZCatalog..I think hurry was inspired by AdvancedQuery. Of course you can define something that implements a particular subset of all possibile types and query types . But when it comes to the point where the functionality is too limited you end up writing you queries based on the functionality the core engine gives you.

-aj


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