[OPEN-ILS-DEV] 1.6 RC1 (and 1.4 and probably before) subject searching

[Dan Scott]

The subject search in bibtemplate, interestingly enough, searches
against the keywords index rather than the subject index.

This might just be a fortuitous mistake, but I suspect it is because
the subject index doesn't currently support searches of compound
subjects composed of topic + temporal + geographic headings.

The subject search:
http://laurentian.concat.ca/opac/en-CA/skin/lul/xml/rresult.xml?rt=subject&tp=subject&t=Great%20Britain%20History%20Wars%20of%20the%20Roses%2C%201455-1485.%20&l=105&d=1&f=&av=
results in 0 hits.

The keyword search:
http://laurentian.concat.ca/opac/en-CA/skin/lul/xml/rresult.xml?rt=keyword&tp=keyword&t=Great%20Britain%20History%20Wars%20of%20the%20Roses%2C%201455-1485.%20&l=105&d=1&f=&av=
results in 5 hits. Some of these hits are because the desired keywords
fall outside of the subject fields, but if you take a record (say,
ISBN 041596864X) and remove all of the pertinent keywords from
non-subject fields, reindex the record and resubmit the keyword
search, you'll see that the keyword search using the compound subject
terms does retrieve the desired record. Or just create a minimal
record with the following field: "651 0. ‡aGreat Britain ‡xHistory
‡yWars of the Roses, 1455-1485."

If you peek at the metabib.subject_field_entry table, you'll see that
the subject terms are all there, but broken up across entries.
Presumably, this is why the compound search doesn't find a hit against
them.

One way that I documented back in February
(http://coffeecode.net/archives/183-Evergreen-Exposed-introduction-to-Evergreen-development-OLA-2009.html)
of resolving this problem is to add an additional entry to the subject
search index:

INSERT INTO config.metabib_field (field_class, name, xpath, weight,
format, search_field)
   VALUES ('subject', 'flat', '//mods32:mods/mods32:subject//text()',
1, 'mods32', 't');

Once that has been added, you can reindex all of your records and
compound subject searches will work as expected.

However, I would suggest that it would be better to have this as part
of the default search indexes in 1.6 - and that the bibtemplate
subject search should then be adjusted to search the subject index
accordingly, to avoid false positives that occur when using the
keyword index.