[ZOOM] hello and first impressions of the C++ bindings

Robert Sanderson azaroth at liverpool.ac.uk
Mon Nov 5 13:59:23 CET 2001


> >I recall a conversation on the ZIG bus about what is returned for GRS1
> >in this, but not the outcome. I -think- it was an implementation specific
> >rendition of the GRS1. (I hope so at least, because that's why my
> >implementation will need to return to TCL)
> I think at least later on the list, we agreed that for the ASN.1-defined 
> structured records (with the exception of SUTRS), it didn't make much sense 
> to return the BER-buffer... mostly because you would need ASN.1/BER tools 

Goodo :)

>  > - Howto is one access multible database on the same target. i am missing
> > >   a list of databases as part of the search class.

> >I think that's beyond scope, in the same way that multiple targets is.

> That doesn't make sense to me. The fact that the database is a list is a 
> basic part of the protocol... why would that be out of scope? We also need 
> a "database" value associated with each record object.

I think that the resultset should maintain the database, and the record 
maintain the resultset. So record->resultset->database.  This seems 
simpler to me than having it copied to the record object as well.
(Though ... you could in theory delete the resultset and not all records 
associated with it, but then what use is just the name of the database and 
not all the other information on the resultset and connection objects?)


There's vast cans of worms to be opened if we allow multi database 
searches from a single request, which I personally feel isn't something 
that ZOOM should be handling.  If we can search multiple databases on a 
single target, then we should allow searching multiple databases across 
multiple targets IMO.

For example:

My server has the following databases:

* mailarchive  (simple XML rendition of an email list archive)
* LCSH         (the lcsh in marc authority)
* scifi        (marc bibliographic data)
* eadhub       (EAD XML)
* unesco       (Unesco thesaurus in proprietary xml)
* transcript   (TEI transcription in middle french (my PhD))
* IR-Explain-1

etc.

Searching scifi and lcsh with MARC as the record syntax will work fine, 
but the data is largely incongruous.
Returning XML will work for all of them, but the XML records will be 
completely different.
GRS1 will work for all of them, but you have the same problem as XML.
SUTRS just returns the XML for most of them.

Error handling will become much messier as, say, my EAD database refuses 
to return MARC but scifi returns it fine. 

I've not looked at the spec for this (never needed to) but I assume that 
only one resultset is created for the combined search? Or does it create 
one resultset for each database? There seems to be nasty issues with both 
ways.  (eg distinguishing origin of records, vs somehow returning multiple 
result sets)

Encapsulation of search and sort is, now, part of the protocol but I don't 
think we need to have that either ;)

Rob

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