Really fix SQLite savepoints unlike the shortsighted 398215b1
[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / ResultClass / HashRefInflator.pm
CommitLineData
b0930c1e 1package DBIx::Class::ResultClass::HashRefInflator;
2
83304545 3use strict;
4use warnings;
5
137c657c 6=head1 NAME
7
b24d86a1 8DBIx::Class::ResultClass::HashRefInflator - Get raw hashrefs from a resultset
137c657c 9
10=head1 SYNOPSIS
11
a5b29361 12 use DBIx::Class::ResultClass::HashRefInflator;
13
137c657c 14 my $rs = $schema->resultset('CD');
137c657c 15 $rs->result_class('DBIx::Class::ResultClass::HashRefInflator');
a5b29361 16 while (my $hashref = $rs->next) {
630ba6e5 17 ...
18 }
19
20 OR as an attribute:
21
22 my $rs = $schema->resultset('CD')->search({}, {
23 result_class => 'DBIx::Class::ResultClass::HashRefInflator',
24 });
25 while (my $hashref = $rs->next) {
26 ...
a5b29361 27 }
137c657c 28
29=head1 DESCRIPTION
30
8273e845 31DBIx::Class is faster than older ORMs like Class::DBI but it still isn't
a5b29361 32designed primarily for speed. Sometimes you need to quickly retrieve the data
fb13a49f 33from a massive resultset, while skipping the creation of fancy result objects.
a5b29361 34Specifying this class as a C<result_class> for a resultset will change C<< $rs->next >>
35to return a plain data hash-ref (or a list of such hash-refs if C<< $rs->all >> is used).
137c657c 36
a5b29361 37There are two ways of applying this class to a resultset:
2328814a 38
a5b29361 39=over
137c657c 40
a5b29361 41=item *
137c657c 42
a5b29361 43Specify C<< $rs->result_class >> on a specific resultset to affect only that
44resultset (and any chained off of it); or
137c657c 45
a5b29361 46=item *
137c657c 47
a5b29361 48Specify C<< __PACKAGE__->result_class >> on your source object to force all
49uses of that result source to be inflated to hash-refs - this approach is not
50recommended.
137c657c 51
a5b29361 52=back
137c657c 53
54=cut
b0930c1e 55
2328814a 56##############
57# NOTE
58#
a5b29361 59# Generally people use this to gain as much speed as possible. If a new &mk_hash is
2328814a 60# implemented, it should be benchmarked using the maint/benchmark_hashrefinflator.pl
9839286b 61# script (in addition to passing all tests of course :)
2328814a 62
a5b29361 63# This coderef is a simple recursive function
fd4b0742 64# Arguments: ($me, $prefetch, $is_root) from inflate_result() below
a5b29361 65my $mk_hash;
66$mk_hash = sub {
7f7f54cd 67
68 my $hash = {
52864fbd 69
7f7f54cd 70 # the main hash could be an undef if we are processing a skipped-over join
71 $_[0] ? %{$_[0]} : (),
72
73 # the second arg is a hash of arrays for each prefetched relation
52864fbd 74 map { $_ => (
75
76 # null-branch or not
77 ref $_[1]->{$_} eq $DBIx::Class::ResultSource::RowParser::Util::null_branch_class
78
79 ? ref $_[1]->{$_}[0] eq 'ARRAY' ? [] : undef
80
81 : ref $_[1]->{$_}[0] eq 'ARRAY'
82 ? [ map { $mk_hash->( @$_ ) || () } @{$_[1]->{$_}} ]
83 : $mk_hash->( @{$_[1]->{$_}} )
84
85 ) } ($_[1] ? keys %{$_[1]} : ())
7f7f54cd 86 };
87
52864fbd 88 ($_[2] || keys %$hash) ? $hash : undef;
a5b29361 89};
90
a5b29361 91=head1 METHODS
92
a5b29361 93=head2 inflate_result
94
95Inflates the result and prefetched data into a hash-ref (invoked by L<DBIx::Class::ResultSet>)
96
97=cut
98
e1540ee0 99##################################################################################
100# inflate_result is invoked as:
101# HRI->inflate_result ($resultsource_instance, $main_data_hashref, $prefetch_data_hashref)
a5b29361 102sub inflate_result {
7f7f54cd 103 return $mk_hash->($_[2], $_[3], 'is_root');
2328814a 104}
105
a2bd3796 1061;
107
108__END__
a5b29361 109
110=head1 CAVEATS
111
112=over
113
114=item *
419ff184 115
116This will not work for relationships that have been prefetched. Consider the
117following:
118
119 my $artist = $artitsts_rs->search({}, {prefetch => 'cds' })->first;
120
121 my $cds = $artist->cds;
122 $cds->result_class('DBIx::Class::ResultClass::HashRefInflator');
8273e845 123 my $first = $cds->first;
419ff184 124
8273e845 125C<$first> will B<not> be a hashref, it will be a normal CD row since
419ff184 126HashRefInflator only affects resultsets at inflation time, and prefetch causes
127relations to be inflated when the master C<$artist> row is inflated.
128
088476d4 129=item *
130
131Column value inflation, e.g., using modules like
132L<DBIx::Class::InflateColumn::DateTime>, is not performed.
133The returned hash contains the raw database values.
134
a5b29361 135=back
136
a2bd3796 137=head1 FURTHER QUESTIONS?
419ff184 138
a2bd3796 139Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>.
140
141=head1 COPYRIGHT AND LICENSE
142
143This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE>
144by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can
145redistribute it and/or modify it under the same terms as the
146L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>.