NexTrieve::Query - handle the Query specifications of NexTrieve
use NexTrieve; $ntv = NexTrieve->new( | {method => value} ); $query = $ntv->Query( | file | xml | {method => value} );
The Query object of the Perl support for NexTrieve. Do not create directly, but through the Query method of the NexTrieve object.
The following methods are available to the NexTrieve::Query object.
Please note that all methods described here are directly related to the Query XML as described on http://www.nextrieve.com/usermanual/2.0.0/ntvqueryxml.stm . Any new feautures of NexTrieve should probably be supported by these methods, as no filtering is taking place before the Query XML is generated.
$query->ampersandize( $constraint = 'attr1 = 1 & attr2 = 2' ); $query->constraint( $constraint ); $constraint = $query->constraint;
The "constraint" method allows you to specify the constraint that should be applied to the list of documents that is going to be searched. A full list of constraint capabilities can be found on http://www.nextrieve.com/usermanual/2.0.0/ntvqueryxml.stm . Please make sure that the constraint is valid XML, most notably by making sure that '&' is expressed as '&' and '<' is expressed as '<'. This can be achieved by converting the query with the ampersandize method that is inherited
$query->displayedhits( number ); $displayedhits = $query->displayedhits;
The "displayedhits" method sets the maximum number of hits that you want to have returned to you. It is an alternate way of using the lasthit method. If neither the lasthit or the "displayedhits" method is called on the object, the number of hits to be returned is determined by what was specified by the totalhits method.
$query->firsthit( ordinal ); $firsthit = $query->firsthit;
The "firsthit" method allows you to specify the ordinal number of the first hit that you want returned. This is particularly useful when "paging" through a result list. Either call the lasthit method to specify the ordinal number of the last hit you want returned, or the displayedhits method to specify the maximum number of hits you want returned.
The value "1" is assumed if the firsthit method is never called.
$query->fuzzylevel( 0 | 1 | 2 | 3 ); $fuzzylevel = $query->fuzzylevel;
The "fuzzylevel" method allows you to specify the fuzzyness of the search that should be used. It is only applicable if the value "fuzzy" was specified with a call to method type.
Currently only the values 0, 1, 2 and 3 are allowed. By default, a value of "1" is assumed if the "fuzzylevel" method is never called.
$query->highlightlength( 0 | number ); $highlightlength = $query->highlightlength;
The "highlightlength" method allows you to specify the number of characters that should be in a word to have the word highlighted in the preview of a hit. It is only applicable if the value "fuzzy" was specified with a call to method type.
The value "0" indicates an automatic length determination that uses the length of the words specified in the query, qany, qall and qnot methods.
The value "3" is assumed if the "highlightlength" method is never called.
$query->id( id ); $id = $query->id;
The "id" method is of little use with the Perl modules: it is used by the NexTrieve server to identify queries with results that are offered to the server using a persistent connection. Since the Perl modules always break the connection after receiving a result, there is not much point in using this feature.
The input parameter specifies a string that uniquely identifies this query. If specified, the same string will be returned by the "id" method of the NexTrieve::Hitlist object.
$query->indexname( mnemonic ); $indexname = $query->indexname;
The "indexname" method is only applicable when using a Caching Query Server, as described on http://www.nextrieve.com/usermanual/2.0.0/ntvcached.stm .
The "indexname" method specifies the name of the logical index that should be used for this query. No logical index will be assumed if this method is never called.
$query->lasthit( $ordinal ); $lasthit -> $query->lasthit;
The "lasthit" method specifies the ordinal number of the last hit that you want to have returned. As such, it is an alternative way for using the displayedhits method. The ordinal number of the last possible hit, as specified with a call to the totalhits method, will be assumed if this method is never called.
$query->qall( qw(all of these words must occur) ); $qall = $query->qall;
The "qall" method specifies a list of words that should all occur in a hit. It is an alternative way to specifying words using the "+" prefix in the query method.
$query->qany( qw(all of these words may occur) ); $qany = $query->qany;
The "qany" method specifies a list of words that may or may not occur in a hit. It is an alternative way to specifying words without any prefix in the query method.
$query->qnot( qw(none of these words may occur) ); $qnot = $query->qnot;
The "qnot" method specifies a list of words that should not occur in a hit. It is an alternative way to specifying words using the "-" prefix in the query method.
$query->query( qw(+must may -maynot) ); $queryspec = $query->query;
The "query" method specifies the query for which a hitlist should be returned. It can consist of just a bunch of words. If an exact search is specified with the type method, then the words can be prefixed with:
"+" to indicate a word that B<must> occur in a document "-" to indicate a word that must B<not> occur in a document
The "query" method is an alternative to calling the qall, qany or qnot methods.
$query->showattributes( true | false ); $showattributes = $query->showattributes;
The "showattributes" method allows you to specify whether you want the attributes associated with a document, to be returned with the hit. By default attributes are returned with the hit and can be obtained by the "attributes" method of the NexTrieve::Hitlist::Hit object.
Please note that in the future it may become possible to indicate specific attributes to be returned, which will change the meaning of the input parameters. It is therefore recommended to only use the values "0" and "1" as parameters to this method, so that future versions of this method can remain compatible.
$query->showpreviews( true | false ); $showpreviews = $query->showpreviews;
The "showpreviews" method allows you to specify whether you want a preview of the text where the hit was found in a document, to be returned with the hit. By default the preview is returned with the hit and can be obtained by the "preview" method of the NexTrieve::Hitlist::Hit object.
$query->texttype( name,weight ); ($weight) = $query->texttype( name );
The "texttype" method specifies the weight that should be applied to text found in the given text type name.
The first input parameter specifies the "name" of the texttype.
The second input parameter specifies the "weight" of the texttype that should be used in the query. A default of "100" will be assumed if no weight is specified.
$resource->texttypes( [name1,weight1], [name2..] .. [nameN..] ); @texttype = $resource->texttypes;
The "texttypes" method allows you to weight ot all texttypes that have to have a weight different from the default weight of "100". Each input parameter specifies the specifics of one texttype as a reference to a list in which the parameters have the same order as the texttype method.
$query->totalhits( number ); $totalhits = $query->totalhits;
The "totalhits" method specifies how many hits should initially be considered for inclusion in the hitlist. A default of "1000" is assumed if this method is never called.
The actual number of hits returned is determined by the firsthit and displayedhits or lasthit method.
$query->type( exact | fuzzy ); $type = $query->type;
The "type" method indicates which type of search should be performed. By default a "fuzzy" search will be performed if this method is never called. Currently, there are two values that can be specified:
- exact
Each word should occur exactly as specified in the document.
- fuzzy
A context sensitive pattern algorithm is used to search for hits. Words do not need to be spelled exactly, but exactly spelled words are favoured over misspelt words.
Elizabeth Mattijsen, <liz@dijkmat.nl>.
Please report bugs to <perlbugs@dijkmat.nl>.
NexTrieve is no longer being supported.
Copyright (c) 1995-2003 Elizabeth Mattijsen <liz@dijkmat.nl>. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
The NexTrieve.pm and the other NexTrieve::xxx modules.
To install NexTrieve, copy and paste the appropriate command in to your terminal.
cpanm
cpanm NexTrieve
CPAN shell
perl -MCPAN -e shell install NexTrieve
For more information on module installation, please visit the detailed CPAN module installation guide.