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.IX Title "DBIx::Class::Helper::ResultSet::SetOperations 3pm"
.TH DBIx::Class::Helper::ResultSet::SetOperations 3pm "2022-12-06" "perl v5.36.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
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.SH "NAME"
DBIx::Class::Helper::ResultSet::SetOperations \- Do set operations with DBIx::Class
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& package MyApp::Schema::ResultSet::Foo;
\&
\& _\|_PACKAGE_\|_\->load_components(qw{Helper::ResultSet::SetOperations});
\&
\& ...
\&
\& 1;
.Ve
.PP
And then elsewhere, like in a controller:
.PP
.Vb 3
\& my $rs1 = $rs\->search({ foo => \*(Aqbar\*(Aq });
\& my $rs2 = $rs\->search({ baz => \*(Aqbiff\*(Aq });
\& for ($rs1\->union($rs2)\->all) { ... }
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This component allows you to use various set operations with your ResultSets.
See \*(L"\s-1NOTE\*(R"\s0 in DBIx::Class::Helper::ResultSet for a nice way to apply it to your
entire schema.
.PP
Component throws exceptions if ResultSets have different ResultClasses or
different \*(L"Columns Specs.\*(R"
.PP
The basic idea here is that in \s-1SQL\s0 if you use a set operation they must be
selecting the same columns names, so that the results will all match.  The deal
with the ResultClasses is that \s-1DBIC\s0 needs to inflate the results the same for
the entire ResultSet, so if one were to try to apply something like a union in
a table with the same column name but different classes \s-1DBIC\s0 wouldn't be doing
what you would expect.
.PP
A nice way to use this is with DBIx::Class::ResultClass::HashRefInflator.
.PP
You might have something like the following sketch autocompletion code:
.PP
.Vb 7
\& my $rs1 = $schema\->resultset(\*(AqAlbum\*(Aq)\->search({
\&    name => { \-like => "$input%" }
\& }, {
\&   columns => [qw( id name ), {
\&      tablename => \e[\*(Aq?\*(Aq, [{} => \*(Aqalbum\*(Aq]],
\&   }],
\& });
\&
\& my $rs2 = $schema\->resultset(\*(AqArtist\*(Aq)\->search({
\&    name => { \-like => "$input%" }
\& }, {
\&   columns => [qw( id name ), {
\&      tablename => \e[\*(Aq?\*(Aq, [{} => \*(Aqartist\*(Aq]],
\&   }],
\& });
\&
\& my $rs3 = $schema\->resultset(\*(AqSong\*(Aq)\->search({
\&    name => { \-like => "$input%" }
\& }, {
\&   columns => [qw( id name ), {
\&      tablename => \e[\*(Aq?\*(Aq, [{} => \*(Aqsong\*(Aq]],
\&   }],
\& });
\&
\& $_\->result_class(\*(AqDBIx::Class::ResultClass::HashRefInflator\*(Aq)
\&   for ($rs1, $rs2, $rs3);
\&
\& my $data = [$rs1\->union([$rs2, $rs3])\->all];
.Ve
.SH "METHODS"
.IX Header "METHODS"
.SS "union"
.IX Subsection "union"
.SS "union_all"
.IX Subsection "union_all"
.SS "intersect"
.IX Subsection "intersect"
.SS "intersect_all"
.IX Subsection "intersect_all"
.SS "except"
.IX Subsection "except"
.SS "except_all"
.IX Subsection "except_all"
All of these methods take a single ResultSet or an ArrayRef of ResultSets as
the parameter only parameter.
.PP
On Oracle \f(CW\*(C`except\*(C'\fR will issue a \f(CW\*(C`MINUS\*(C'\fR operation.
.SH "AUTHOR"
.IX Header "AUTHOR"
Arthur Axel \*(L"fREW\*(R" Schmidt <frioux+cpan@gmail.com>
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
This software is copyright (c) 2020 by Arthur Axel \*(L"fREW\*(R" Schmidt.
.PP
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.