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From "Erick Erickson" <erickerick...@gmail.com>
Subject Re: Fields
Date Mon, 19 Feb 2007 16:18:30 GMT
It's whatever you set it to. From the API...

QueryParser

public *QueryParser*(String
<http://java.sun.com/j2se/1.4/docs/api/java/lang/String.html> f,
                   Analyzer
<file:///C:/lucene-2.1.0/docs/api/org/apache/lucene/analysis/Analyzer.html>
a)

Constructs a query parser.

*Parameters:*f - the default field for query terms.a - used to find terms in
the query text.

Note: this is the 2.1 API (idential to 2.0 as I remember).


On 2/19/07, Kainth, Sachin <Sachin.Kainth@atkinsglobal.com> wrote:
>
> Hi Erik,
>
> I looked at the QueryParser API doc but I can't seem to find what the
> default field is. Also, how would the syntax of the index code differ
> when indexing a word to the default field from this:
>
> Doc.Add(Field.Text("album", Album));
>
> Cheers
>
> Sachin
>
> -----Original Message-----
> From: Erick Erickson [mailto:erickerickson@gmail.com]
> Sent: 19 February 2007 16:05
> To: java-user@lucene.apache.org
> Subject: Re: Fields
>
> See below.
>
> On 2/19/07, Kainth, Sachin <Sachin.Kainth@atkinsglobal.com> wrote:
> >
> > Hi all,
> >
> > I have a few question regarding indexing documents.
> >
> > 1. With my experience of indexing documents with lucene so far I have
> > done things like:
> >
> > Doc.Add(Field.Text("album", Album));
> >
> > Where Album is a string representing an album name.  Now with this
> > sort of indexing what I do is a search such as:
> >
> > "album:Thriller"
> >
> > a) Does this mean that I cannot do an search across all fields  by
> > submitting the query:
> >
> > "Thriller"?  In other words by submitting this query would my code
> > search all fields?
>
>
> No. If you just submit "Thriller", you'll only search the default field.
> See QueryParser for the default field.
>
>
> b) Is there a way in which I can index elements of a document without
> > naming the field.  What would the impact of such a use of the indexing
>
> > capabilities of Lucene be?
>
>
> I don't think this makes sense in Lucene terms. All elements in a
> document have a field. You can index everything into one field if you
> need an aggregate, which gives you this same result.
>
> Do note, however, that there's no requirement that all documents have
> the same fields.
>
>
> 2. Is there a limit to the number of
> > a) named fields per document that I can store
>
>
> I think there is, but it's absurdly high. Don't worry about this....
>
>
> b) non-named fields per document that I can store
>
>
> 0 since I don't think you can.
>
>
> 3.
> >
> > a) Is it possible in Lucene to conduct searches that are very complex
> > such as:
> >
> > ((album = Thriller AND artist = (Michael OR Jackson)) OR (date between
> X
> > AND Y)) AND (label = sony OR Epic)   etc...
>
>
> Yes
>
>
> b) For such a query what are the performance penalties compared to a
> > simple search involving 1 term?
>
>
> In the immortal words of Mr. Hatcher.. .it depends. You'll really just
> have to experiment and find out. It can probably be approximated by
> taking the sum of the individual queries as the upper limit. The real
> killer is wildcards..... The real question isn't "what is the effect on
> performance", it's "is the performance good enough for my application".
> Which varies as the characteristics of the database change.
>
> I would argue that a 1M index will process arbitrarily complex queries
> "fast enough". The same may not be true for a 100G index. So this
> question is really unanswerable in the abstract.
>
>
> Cheers
> >
> > Sachin
> >
> >
> >
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