Merge branch 'master' into topic/constructor_rewrite

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / SQLMaker / OracleJoins.pm

diff --git a/lib/DBIx/Class/SQLMaker/OracleJoins.pm b/lib/DBIx/Class/SQLMaker/OracleJoins.pm
new file mode 100644 (file)
index 0000000..b95c56e
--- /dev/null
+++ b/lib/DBIx/Class/SQLMaker/OracleJoins.pm
@@ -0,0 +1,168 @@
+package DBIx::Class::SQLMaker::OracleJoins;
+
+use warnings;
+use strict;
+
+use base qw( DBIx::Class::SQLMaker::Oracle );
+
+sub select {
+  my ($self, $table, $fields, $where, $rs_attrs, @rest) = @_;
+
+  # pull out all join conds as regular WHEREs from all extra tables
+  if (ref($table) eq 'ARRAY') {
+    $where = $self->_oracle_joins($where, @{ $table }[ 1 .. $#$table ]);
+  }
+
+  return $self->next::method($table, $fields, $where, $rs_attrs, @rest);
+}
+
+sub _recurse_from {
+  my ($self, $from, @join) = @_;
+
+  my @sqlf = $self->_from_chunk_to_sql($from);
+
+  for (@join) {
+    my ($to, $on) = @$_;
+
+    if (ref $to eq 'ARRAY') {
+      push (@sqlf, $self->_recurse_from(@{ $to }));
+    }
+    else {
+      push (@sqlf, $self->_from_chunk_to_sql($to));
+    }
+  }
+
+  return join q{, }, @sqlf;
+}
+
+sub _oracle_joins {
+  my ($self, $where, @join) = @_;
+  my $join_where = $self->_recurse_oracle_joins(@join);
+
+  if (keys %$join_where) {
+    if (!defined($where)) {
+      $where = $join_where;
+    } else {
+      if (ref($where) eq 'ARRAY') {
+        $where = { -or => $where };
+      }
+      $where = { -and => [ $join_where, $where ] };
+    }
+  }
+  return $where;
+}
+
+sub _recurse_oracle_joins {
+  my $self = shift;
+
+  my @where;
+  for my $j (@_) {
+    my ($to, $on) = @{ $j };
+
+    push @where, $self->_recurse_oracle_joins(@{ $to })
+      if (ref $to eq 'ARRAY');
+
+    my $join_opts  = ref $to eq 'ARRAY' ? $to->[0] : $to;
+    my $left_join  = q{};
+    my $right_join = q{};
+
+    if (ref $join_opts eq 'HASH' and my $jt = $join_opts->{-join_type}) {
+      #TODO: Support full outer joins -- this would happen much earlier in
+      #the sequence since oracle 8's full outer join syntax is best
+      #described as INSANE.
+      $self->throw_exception("Can't handle full outer joins in Oracle 8 yet!\n")
+        if $jt =~ /full/i;
+
+      $left_join  = q{(+)} if $jt =~ /left/i
+        && $jt !~ /inner/i;
+
+      $right_join = q{(+)} if $jt =~ /right/i
+        && $jt !~ /inner/i;
+    }
+
+    # sadly SQLA treats where($scalar) as literal, so we need to jump some hoops
+    push @where, map { \sprintf ('%s%s = %s%s',
+      ref $_ ? $self->_recurse_where($_) : $self->_quote($_),
+      $left_join,
+      ref $on->{$_} ? $self->_recurse_where($on->{$_}) : $self->_quote($on->{$_}),
+      $right_join,
+    )} keys %$on;
+  }
+
+  return { -and => \@where };
+}
+
+1;
+
+=pod
+
+=head1 NAME
+
+DBIx::Class::SQLMaker::OracleJoins - Pre-ANSI Joins-via-Where-Clause Syntax
+
+=head1 PURPOSE
+
+This module is used with Oracle < 9.0 due to lack of support for standard
+ANSI join syntax.
+
+=head1 SYNOPSIS
+
+Not intended for use directly; used as the sql_maker_class for schemas and components.
+
+=head1 DESCRIPTION
+
+Implements pre-ANSI joins specified in the where clause.  Instead of:
+
+    SELECT x FROM y JOIN z ON y.id = z.id
+
+It will write:
+
+    SELECT x FROM y, z WHERE y.id = z.id
+
+It should properly support left joins, and right joins.  Full outer joins are
+not possible due to the fact that Oracle requires the entire query be written
+to union the results of a left and right join, and by the time this module is
+called to create the where query and table definition part of the sql query,
+it's already too late.
+
+=head1 METHODS
+
+=over
+
+=item select
+
+Overrides DBIx::Class::SQLMaker's select() method, which calls _oracle_joins()
+to modify the column and table list before calling next::method().
+
+=back
+
+=head1 BUGS
+
+Does not support full outer joins (however neither really does DBIC itself)
+
+=head1 SEE ALSO
+
+=over
+
+=item L<DBIx::Class::Storage::DBI::Oracle::WhereJoins> - Storage class using this
+
+=item L<DBIx::Class::SQLMaker> - Parent module
+
+=item L<DBIx::Class> - Duh
+
+=back
+
+=head1 AUTHOR
+
+Justin Wheeler C<< <jwheeler@datademons.com> >>
+
+=head1 CONTRIBUTORS
+
+David Jack Olrik C<< <djo@cpan.org> >>
+
+=head1 LICENSE
+
+This module is licensed under the same terms as Perl itself.
+
+=cut
+