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From "Erick Erickson" <erickerick...@gmail.com>
Subject Re: Why indexing database is necessary? (RE: indexing database)
Date Wed, 05 Mar 2008 01:10:24 GMT
And one other point. You probably *don't* need a search engine for your
database *if* you don't have much textual data. That is, if your database
consists of "classical" tables with columns like "firstname", "lastname",
etc.

But if your database has columns in it containing, say, a page of text then
searching that text is a real pain. *That's* where a search engine shines.

Searching a large DB text field for a single word becomes...er...awkward.

That said, there's a long thread on the Lucene thread that I didn't
understand
at all concerning embedding Lucene in Oracle. You might try looking at
the searchable Lucene threads for that...

Best
Erick

On Tue, Mar 4, 2008 at 5:27 PM, Chris Lu <chris.lu@gmail.com> wrote:

> Hi, Nick,
>
> Lucene Index in a sense is more like another kind of database indexes,
> because it's inverted, etc.
>
> If we ask why we need many database indexes, the answer is, different
> query execution path.
> Same thing for Lucene index, which is faster for term matching.
>
> Lucene index actually can do more. For example, facet-search, which
> tells you how many matches in each category(facet), in addition to the
> matched results. This way is more convenient for websites to display
> results, and provide additional links for users to narrow down the
> results.
>
> --
> Chris Lu
> -------------------------
> Instant Scalable Full-Text Search On Any Database/Application
> site: http://www.dbsight.net
> demo: http://search.dbsight.com
> Lucene Database Search in 3 minutes:
>
> http://wiki.dbsight.com/index.php?title=Create_Lucene_Database_Search_in_3_minutes
> DBSight customer, a shopping comparison site, (anonymous per request)
> got 2.6 Million Euro funding!
>
>
> On Tue, Mar 4, 2008 at 11:28 AM, Duan, Nick <NDuan@mcdonaldbradley.com>
> wrote:
> > Hmm, I guess that's because a database query returns a list of records,
> >  whereas search engine returns only the links, not the actual content.
> >  So a search engine works only in the index space, whereas a database
> >  query engine would have to work in both index and content space...
> >
> >
> >  ND
> >
> >
> >
> >  -----Original Message-----
> >  From: Will Johnson [mailto:willjohnsonsearch@gmail.com]
> >  Sent: Tuesday, March 04, 2008 2:18 PM
> >  To: java-user@lucene.apache.org
> >  Subject: RE: Why indexing database is necessary? (RE: indexing
> database)
> >
> >  Don't forget the number 1 reason: speed.  For certain types of queries
> a
> >  search engine can return results orders of magnitude faster than a
> >  database.
> >  I've seen search engines return hits in hundreds of milliseconds when
> >  the
> >  same database query took hours or even days.  That's not to say that a
> >  search engine is always better, just the it often times is for when the
> >  inputs and outputs are carefully defined.
> >
> >  - will
> >
> >  -----Original Message-----
> >  From: Darren Hartford [mailto:dhartford@ghsinc.com]
> >  Sent: Tuesday, March 04, 2008 1:52 PM
> >  To: java-user@lucene.apache.org
> >  Subject: RE: Why indexing database is necessary? (RE: indexing
> database)
> >
> >  Indexing with lucene/nutch on top of/instead of DB indexing for:
> >
> >  1) relativity scoring
> >  2) alias searching (i.e. a large amount of aliases, like first names)
> >  3) highlighting
> >  4) cross-datasource searching (multi DB, DB + XML files, etc).
> >
> >  As for best approach to externally index, I do not have any direct
> >  pointers.  I would recommend looking at an ETL tool that can be
> extended
> >  for this purpose (I've started writing a plugin for Pentaho, but got
> >  pulled off and haven't finished it -- and that was for Solr, not
> >  lucene/nutch).
> >
> >  -D
> >
> >  > -----Original Message-----
> >  > From: Duan, Nick [mailto:NDuan@mcdonaldbradley.com]
> >  > Sent: Tuesday, March 04, 2008 1:33 PM
> >  > To: java-user@lucene.apache.org
> >  > Subject: Why indexing database is necessary? (RE: indexing database)
> >  >
> >  > Could anyone provide any insight on why someone would use
> nutch/lucene
> >  > or any other search engines to index relational databases? With use
> >  > cases if possible?  Shouldn't the database's own indexing mechanism
> be
> >  > used since it is more efficient?
> >  >
> >  > If there is such a need of indexing the database content using search
> >  > engines, what would be the best approach other than de-normalizing
> the
> >  > database?
> >  >
> >  > Thanks a lot in advance!
> >  >
> >  > ND
> >  > -----Original Message-----
> >  > From: payo [mailto:payo22@yahoo.com]
> >  > Sent: Tuesday, March 04, 2008 12:36 PM
> >  > To: nutch-user@lucene.apache.org
> >  > Subject: indexing database
> >  >
> >  >
> >  > hi to all
> >  >
> >  > i can index a database with nutch?
> >  >
> >  > i am use nutch 0.8.1
> >  >
> >  > thanks
> >  > --
> >  > View this message in context:
> >  > http://www.nabble.com/indexing-database-tp15832696p15832696.html
> >  > Sent from the Nutch - User mailing list archive at Nabble.com.
> >  >
> >  >
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> >
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