1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
package DBIx::Class::ResultSource::View;
use strict;
use warnings;
use DBIx::Class::ResultSet;
use base qw/DBIx::Class/;
__PACKAGE__->load_components(qw/ResultSource/);
__PACKAGE__->mk_group_accessors(
'simple' => qw(is_virtual view_definition)
);
=head1 NAME
DBIx::Class::ResultSource::View - ResultSource object representing a view
=head1 SYNOPSIS
package MyDB::Schema::Result::Year2000CDs;
use base qw/DBIx::Class::Core/;
__PACKAGE__->table_class('DBIx::Class::ResultSource::View');
__PACKAGE__->table('year2000cds');
__PACKAGE__->result_source_instance->is_virtual(1);
__PACKAGE__->result_source_instance->view_definition(
"SELECT cdid, artist, title FROM cd WHERE year ='2000'"
);
__PACKAGE__->add_columns(
'cdid' => {
data_type => 'integer',
is_auto_increment => 1,
},
'artist' => {
data_type => 'integer',
},
'title' => {
data_type => 'varchar',
size => 100,
},
);
=head1 DESCRIPTION
View object that inherits from L<DBIx::Class::ResultSource>
This class extends ResultSource to add basic view support.
A view has a L</view_definition>, which contains a SQL query. The query can
only have parameters if L</is_virtual> is set to true. It may contain JOINs,
sub selects and any other SQL your database supports.
View definition SQL is deployed to your database on
L<DBIx::Class::Schema/deploy> unless you set L</is_virtual> to true.
Deploying the view does B<not> translate it between different database
syntaxes, so be careful what you write in your view SQL.
Virtual views (L</is_virtual> true), are assumed to not
exist in your database as a real view. The L</view_definition> in this
case replaces the view name in a FROM clause in a subselect.
=head1 EXAMPLES
Having created the MyDB::Schema::Year2000CDs schema as shown in the SYNOPSIS
above, you can then:
$2000_cds = $schema->resultset('Year2000CDs')
->search()
->all();
$count = $schema->resultset('Year2000CDs')
->search()
->count();
If you modified the schema to include a placeholder
__PACKAGE__->result_source_instance->view_definition(
"SELECT cdid, artist, title FROM cd WHERE year ='?'"
);
and ensuring you have is_virtual set to true:
__PACKAGE__->result_source_instance->is_virtual(1);
You could now say:
$2001_cds = $schema->resultset('Year2000CDs')
->search({}, { bind => [2001] })
->all();
$count = $schema->resultset('Year2000CDs')
->search({}, { bind => [2001] })
->count();
=head1 SQL EXAMPLES
=over
=item is_virtual set to false
$schema->resultset('Year2000CDs')->all();
SELECT cdid, artist, title FROM year2000cds me
=item is_virtual set to true
$schema->resultset('Year2000CDs')->all();
SELECT cdid, artist, title FROM
(SELECT cdid, artist, title FROM cd WHERE year ='2000') me
=back
=head1 METHODS
=head2 is_virtual
__PACKAGE__->result_source_instance->is_virtual(1);
Set to true for a virtual view, false or unset for a real
database-based view.
=head2 view_definition
__PACKAGE__->result_source_instance->view_definition(
"SELECT cdid, artist, title FROM cd WHERE year ='2000'"
);
An SQL query for your view. Will not be translated across database
syntaxes.
=head1 OVERRIDDEN METHODS
=head2 from
Returns the FROM entry for the table (i.e. the view name)
or the SQL as a subselect if this is a virtual view.
=cut
sub from {
my $self = shift;
return \"(${\$self->view_definition})" if $self->is_virtual;
return $self->name;
}
1;
=head1 AUTHORS
Matt S. Trout <mst@shadowcatsystems.co.uk>
With Contributions from:
Guillermo Roditi E<lt>groditi@cpan.orgE<gt>
Jess Robinson <castaway@desert-island.me.uk>
Wallace Reis <wreis@cpan.org>
=head1 LICENSE
You may distribute this code under the same terms as Perl itself.
=cut
|
