Hello Nina, I also always confuse about the search of lucene. The best way is always to use ( ). Field1 AND Field2 OR field3 isn't (Field1 AND Field2) OR field3 !! Why? You can find a good explanation on http://wiki.apache.org/lucene-java/BooleanQuerySyntax
"BooleanQuerySyntax Confusion I found something kind of weird about the way Lucene interprets boolean expressions without parenthesis. when i run the query A AND B OR C, it returns only the documents that have A(in other words as if the query was just the term A). when I run the query A OR B AND C, it returns only the documents that have B AND C(as if the query was just B AND C ). I set the default operator in my application to be AND. can anyone explain this behavior, thanks. Explanation Lucene indeed does some funny stuff with boolean operators. Output the toString of your resultant Query's to see the details, or have a look at the Bugzilla issue that Morus mentions below. First some background: BooleanQuery clauses each have their own set of required/optional/prohibited attributes. Putting operators between them is awkward in the Lucene sense because the parser has to set each clause individually, not in relation to another one. QueryParser takes the most recent operator and applies it to both the clause before and after, and there is no sense of operator precedence (such as in a math expression like 1 + 2 * 3). In the case of A AND B OR C, when the AND is encountered, it sets the required attribute for both A and B, but then when the OR is encountered it sets the optional attribute on B and C, stepping on the previous required flag for B. And similarly with A OR B AND C. I agree that the current behavior is awkward. Is it worth breaking backwards compatibility to correct this with the patch applied? As for the default operator, it is not coming into play in your expression examples because there all clauses have an explicit conjunction that sets the flag. The default operator comes into play for an expression like A B AND C and would be used to set the flag on the A clause. Changing Your Mindset When dealing with Lucene people are strongly encouraged to think in terms of MUST, MUST_NOT and SHOULD (which are represented in the query parser as the prefixes "+", "-" and the default) instead of in terms of AND, OR, and NOT ... Lucene's Boolean Queries (and thus Lucene's QueryParser) is not a strict Boolean Logic system, so it's best not to try and think of it like one. Related Links [WWW] http://www.mail-archive.com/java-user@lucene.apache.org/msg00008.html [WWW] https://issues.apache.org/jira/browse/LUCENE-167 " Best regards Bernadette Claudia Jürgen schrieb: > Hi Nina, > > the advanced search uses (unless otherwise chosen) > AND, i.e. field1 and field2 and field3. > > Whereas in the simple search the terms are connected based on the > configruation property "search.operator" in the dspace.cfg. The default > operator is OR. > > Claudia > > > nina joseph schrieb: > >> Hi All, >> Is the advanced search function searches >> >> (Field1 AND field2 ) OR field3 >> >> OR >> >> Field1 AND (field2 OR field3) >> >> Thank you for your help. >> Nina >> >> >> --------------------------------- >> Never miss an email again! >> Yahoo! Toolbar alerts you the instant new Mail arrives. Check it out. >> >> >> ------------------------------------------------------------------------ >> >> ------------------------------------------------------------------------- >> Take Surveys. Earn Cash. Influence the Future of IT >> Join SourceForge.net's Techsay panel and you'll get the chance to share your >> opinions on IT & business topics through brief surveys-and earn cash >> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> DSpace-tech mailing list >> DSpace-tech@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/dspace-tech >> > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys-and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > DSpace-tech mailing list > DSpace-tech@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/dspace-tech > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ DSpace-tech mailing list DSpace-tech@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dspace-tech
