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package C4::Recommendations; |
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# Copyright 2009,2011 Catalyst IT |
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# |
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# This file is part of Koha. |
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# |
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# Koha is free software; you can redistribute it and/or modify it under the |
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# terms of the GNU General Public License as published by the Free Software |
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# Foundation; either version 2 of the License, or (at your option) any later |
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# version. |
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# |
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# Koha is distributed in the hope that it will be useful, but WITHOUT ANY |
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# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR |
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# A PARTICULAR PURPOSE. See the GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License along with |
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# Koha; if not, write to the Free Software Foundation, Inc., 59 Temple Place, |
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# Suite 330, Boston, MA 02111-1307 USA |
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=head1 NAME |
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C4::Recommendations - Koha module for producing reading recommendations |
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=head1 SYNOPSIS |
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use C4::Recommendations; |
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build_recommendations(); |
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my $recommended_books = get_recommendations($biblio); |
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=head1 DESCRIPTION |
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This looks at the issue history, and counts how many times each particular book |
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has been taken out by someone who also has taken out another particular book, |
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recording that as a hit for each pair. |
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For example, if 3 people have taken out book A and book B, then this is |
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recorded as three "hits" for that combination, and so it'll show as a |
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recommendation with that strength. |
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=head1 EXPORT |
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None by default, however C<build_recommendations> and C<get_recommendations> |
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can be imported optionally. |
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=head1 FUNCTIONS |
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=cut |
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use strict; |
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use warnings; |
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use C4::Context; |
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require Exporter; |
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our @ISA = qw(Exporter); |
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# Items to export into callers namespace by default. Note: do not export |
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# names by default without a very good reason. Use EXPORT_OK instead. |
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# Do not simply export all your public functions/methods/constants. |
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our @EXPORT_OK = qw( |
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build_recommendations |
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get_recommendations |
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); |
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our $VERSION = '0.01'; |
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=head2 build_recommendations |
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build_recommendations |
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This runs through all the issues and generates the tables of recommendations. |
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Note that it'll likely take a long time to run, and put stress on the database, |
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so do it at a low peak time. |
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=cut |
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sub build_recommendations { |
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my $dbh = C4::Context->dbh; |
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$dbh->do("TRUNCATE recommendations"); |
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my $all_issues_query = qq/ |
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SELECT biblio.biblionumber,borrowernumber |
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FROM old_issues,biblio,items |
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WHERE old_issues.itemnumber=items.itemnumber |
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AND items.biblionumber=biblio.biblionumber |
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/; |
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my $all_issues_sth = $dbh->prepare($all_issues_query); |
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my $borrower_issues_query = qq/ |
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SELECT biblio.biblionumber,borrowernumber |
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FROM old_issues,biblio,items |
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WHERE old_issues.itemnumber=items.itemnumber |
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AND items.biblionumber=biblio.biblionumber |
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AND old_issues.borrowernumber = ? |
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AND items.biblionumber > ? |
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/; |
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my $borrower_issues_sth = $dbh->prepare($borrower_issues_query); |
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my $recommendations_select = $dbh->prepare(qq/ |
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SELECT * FROM recommendations |
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WHERE biblio_one = ? AND |
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biblio_two = ? |
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/); |
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my $recommendations_update = $dbh->prepare(qq/ |
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UPDATE recommendations |
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SET hit_count = ? |
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WHERE biblio_one = ? |
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AND biblio_two = ? |
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/); |
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my $recommendations_insert = $dbh->prepare(qq/ |
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INSERT INTO recommendations (biblio_one,biblio_two,hit_count) VALUES (?,?,?) |
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/); |
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$all_issues_sth->execute(); |
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while ( my $issue = $all_issues_sth->fetchrow_hashref() ) { |
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# warn $issue->{'borrowernumber'}; |
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$borrower_issues_sth->execute( $issue->{'borrowernumber'}, $issue->{biblionumber} ); |
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while ( my $borrowers_issue = $borrower_issues_sth->fetchrow_hashref() ) { |
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# warn $borrowers_issue->{'biblionumber'}; |
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$recommendations_select->execute( $issue->{'biblionumber'}, |
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$borrowers_issue->{'biblionumber'} ); |
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if ( my $recommendation = $recommendations_select->fetchrow_hashref() ) { |
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$recommendation->{'hit_count'}++; |
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$recommendations_update->execute( |
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$recommendation->{'hit_count'}, |
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$issue->{'biblionumber'}, |
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$borrowers_issue->{'biblionumber'} |
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); |
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} else { |
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$recommendations_insert->execute( |
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$issue->{'biblionumber'}, |
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$borrowers_issue->{'biblionumber'}, |
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1 |
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); |
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} |
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} |
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} |
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} |
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=head2 get_recommendations |
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my $recommendations = get_recommendations($biblionumber, $limit) |
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foreach my $rec (@$recommendations) { |
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print $rec->{biblionumber}.": ".$rec->{title}."\n"; |
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} |
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This gets the recommendations for a particular biblio, returning an array of |
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hashes containing C<biblionumber> and C<title>. The array is ordered from |
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most-recommended to least. |
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C<$limit> restrictes the amount of results returned. If it's not supplied, |
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it defaults to 100. |
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=cut |
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sub get_recommendations { |
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my ($biblionumber, $limit) = @_; |
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$limit ||= 100; |
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my $dbh = C4::Context->dbh(); |
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# Two parts: first get the biblio_one side, then get the |
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# biblio_two side. I'd love to know how to squish this into one query. |
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my $sth = $dbh->prepare(qq/ |
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SELECT biblio.biblionumber,biblio.title, hit_count |
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FROM biblio,recommendations |
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WHERE biblio.biblionumber = biblio_two |
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AND biblio_one = ? |
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ORDER BY hit_count DESC |
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LIMIT ? |
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/); |
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$sth->execute($biblionumber, $limit); |
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my $res = $sth->fetchall_arrayref({}); |
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$sth = $dbh->prepare(qq/ |
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SELECT biblio.biblionumber,biblio.title, hit_count |
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FROM biblio,recommendations |
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WHERE biblio.biblionumber = biblio_one |
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AND biblio_two = ? |
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ORDER BY hit_count DESC |
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LIMIT ? |
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/); |
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$sth->execute($biblionumber, $limit); |
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push @{ $res }, @{$sth->fetchall_arrayref({})}; |
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$res = \@{ @{$res}[0..$limit] } if (@$res > $limit); |
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my @res = sort { $b->{hit_count} <=> $a->{hit_count} } @$res; |
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return \@res; |
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} |
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1; |
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__END__ |
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=head1 AUTHOR |
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=over |
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=item Chris Cormack, E<lt>chrisc@catalyst.net.nzE<gt> |
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=item Robin Sheat, E<lt>robin@catalyst.net.nzE<gt> |
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=back |
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