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From mark harwood <>
Subject Re: "Advanced" query language
Date Mon, 05 Dec 2005 17:48:29 GMT
> is a more clear syntax have:
> QUERY title,date,size, content WHERE (title LIKE
> 'foo*' OR size>=0)

Let's not forget that unlike most query languages
which are boolean (things either match or they don't)
Lucene has many facilities for influencing the degree
to which matches occur.

A lot of the parameters we need to specify are
controlling this "degree of match" which makes some of
the comparisons with existing boolean query languages
eg XPath or the above seem too simplistic.

We need to express the query tests to be performed
*and* control precisely their score contributions. As
such, a much more complex syntax is required than in a
standard boolean retrieval language.
The existing Lucene Java API models this complexity by
assembling a tree of Query objects. The query language
we create has to recognize that it's role is
ultimately to assemble these same objects which is why
I'm looking more at Ant/Spring-like object assembly
languages rather than taking clues from existing
boolean query languages.

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