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6f4ddea1 |
1 | package # Hide from PAUSE |
2 | DBIx::Class::SQLAHacks::OracleJoins; |
3 | |
4 | use base qw( DBIx::Class::SQLAHacks ); |
5 | |
6 | sub select { |
7 | my ($self, $table, $fields, $where, $order, @rest) = @_; |
8 | |
9 | if (ref($table) eq 'ARRAY') { |
10 | $where = $self->_oracle_joins($where, @{ $table }); |
11 | } |
12 | |
13 | return $self->SUPER::select($table, $fields, $where, $order, @rest); |
14 | } |
15 | |
16 | sub _recurse_from { |
17 | my ($self, $from, @join) = @_; |
18 | |
19 | my @sqlf = $self->_make_as($from); |
20 | |
21 | foreach my $j (@join) { |
22 | my ($to, $on) = @{ $j }; |
23 | |
24 | if (ref $to eq 'ARRAY') { |
25 | push (@sqlf, $self->_recurse_from(@{ $to })); |
26 | } |
27 | else { |
28 | push (@sqlf, $self->_make_as($to)); |
29 | } |
30 | } |
31 | |
32 | return join q{, }, @sqlf; |
33 | } |
34 | |
35 | sub _oracle_joins { |
36 | my ($self, $where, $from, @join) = @_; |
37 | my $join_where = {}; |
38 | $self->_recurse_oracle_joins($join_where, $from, @join); |
39 | if (keys %$join_where) { |
40 | if (!defined($where)) { |
41 | $where = $join_where; |
42 | } else { |
43 | if (ref($where) eq 'ARRAY') { |
44 | $where = { -or => $where }; |
45 | } |
46 | $where = { -and => [ $join_where, $where ] }; |
47 | } |
48 | } |
49 | return $where; |
50 | } |
51 | |
52 | sub _recurse_oracle_joins { |
53 | my ($self, $where, $from, @join) = @_; |
54 | |
55 | foreach my $j (@join) { |
56 | my ($to, $on) = @{ $j }; |
57 | |
58 | if (ref $to eq 'ARRAY') { |
59 | $self->_recurse_oracle_joins($where, @{ $to }); |
60 | } |
61 | |
62 | my $to_jt = ref $to eq 'ARRAY' ? $to->[0] : $to; |
63 | my $left_join = q{}; |
64 | my $right_join = q{}; |
65 | |
66 | if (ref $to_jt eq 'HASH' and exists $to_jt->{-join_type}) { |
67 | #TODO: Support full outer joins -- this would happen much earlier in |
68 | #the sequence since oracle 8's full outer join syntax is best |
69 | #described as INSANE. |
70 | die "Can't handle full outer joins in Oracle 8 yet!\n" |
71 | if $to_jt->{-join_type} =~ /full/i; |
72 | |
73 | $left_join = q{(+)} if $to_jt->{-join_type} =~ /left/i |
74 | && $to_jt->{-join_type} !~ /inner/i; |
75 | |
76 | $right_join = q{(+)} if $to_jt->{-join_type} =~ /right/i |
77 | && $to_jt->{-join_type} !~ /inner/i; |
78 | } |
79 | |
80 | foreach my $lhs (keys %{ $on }) { |
81 | $where->{$lhs . $left_join} = \"= $on->{ $lhs }$right_join"; |
82 | } |
83 | } |
84 | } |
85 | |
86 | 1; |
87 | |
88 | =pod |
89 | |
90 | =head1 NAME |
91 | |
92 | DBIx::Class::SQLAHacks::OracleJoins - Pre-ANSI Joins-via-Where-Clause Syntax |
93 | |
94 | =head1 PURPOSE |
95 | |
96 | This module was originally written to support Oracle < 9i where ANSI joins |
97 | weren't supported at all, but became the module for Oracle >= 8 because |
98 | Oracle's optimising of ANSI joins is horrible. (See: |
99 | http://scsys.co.uk:8001/7495) |
100 | |
101 | =head1 SYNOPSIS |
102 | |
103 | Not intended for use directly; used as the sql_maker_class for schemas and components. |
104 | |
105 | =head1 DESCRIPTION |
106 | |
107 | Implements pre-ANSI joins specified in the where clause. Instead of: |
108 | |
109 | SELECT x FROM y JOIN z ON y.id = z.id |
110 | |
111 | It will write: |
112 | |
113 | SELECT x FROM y, z WHERE y.id = z.id |
114 | |
115 | It should properly support left joins, and right joins. Full outer joins are |
116 | not possible due to the fact that Oracle requires the entire query be written |
117 | to union the results of a left and right join, and by the time this module is |
118 | called to create the where query and table definition part of the sql query, |
119 | it's already too late. |
120 | |
121 | =head1 METHODS |
122 | |
123 | =over |
124 | |
125 | =item select ($\@$;$$@) |
126 | |
127 | Replaces DBIx::Class::SQLAHacks's select() method, which calls _oracle_joins() |
128 | to modify the column and table list before calling SUPER::select(). |
129 | |
130 | =item _recurse_from ($$\@) |
131 | |
132 | Recursive subroutine that builds the table list. |
133 | |
134 | =item _oracle_joins ($$$@) |
135 | |
136 | Creates the left/right relationship in the where query. |
137 | |
138 | =back |
139 | |
140 | =head1 BUGS |
141 | |
142 | Does not support full outer joins. |
143 | Probably lots more. |
144 | |
145 | =head1 SEE ALSO |
146 | |
147 | =over |
148 | |
149 | =item L<DBIx::Class::Storage::DBI::Oracle::WhereJoins> - Storage class using this |
150 | |
151 | =item L<DBIx::Class::SQLAHacks> - Parent module |
152 | |
153 | =item L<DBIx::Class> - Duh |
154 | |
155 | =back |
156 | |
157 | =head1 AUTHOR |
158 | |
159 | Justin Wheeler C<< <jwheeler@datademons.com> >> |
160 | |
161 | =head1 CONTRIBUTORS |
162 | |
163 | David Jack Olrik C<< <djo@cpan.org> >> |
164 | |
165 | =head1 LICENSE |
166 | |
167 | This module is licensed under the same terms as Perl itself. |
168 | |
169 | =cut |
170 | |