requires that the files for 0.1 as created above are available in the
given directory to diff against.
+=head2 select from dual
+
+Dummy tables are needed by some databases to allow calling functions
+or expressions that aren't based on table content, for examples of how
+this applies to various database types, see:
+L<http://troels.arvin.dk/db/rdbms/#other-dummy_table>.
+
+Note: If you're using Oracles dual table don't B<ever> do anything
+other than a select, if you CRUD on your dual table you *will* break
+your database.
+
+Make a table class as you would for any other table
+
+ package MyAppDB::Dual;
+ use strict;
+ use warnings;
+ use base 'DBIx::Class';
+ __PACKAGE__->load_components("Core");
+ __PACKAGE__->table("Dual");
+ __PACKAGE__->add_columns(
+ "dummy",
+ { data_type => "VARCHAR2", is_nullable => 0, size => 1 },
+ );
+
+Once you've loaded your table class select from it using C<select>
+and C<as> instead of C<columns>
+
+ my $rs = $schema->resultset('Dual')->search(undef,
+ { select => [ 'sydate' ],
+ as => [ 'now' ]
+ },
+ );
+
+All you have to do now is be careful how you access your resultset, the below
+will not work because there is no column called 'now' in the Dual table class
+
+ while (my $dual = $rs->next) {
+ print $dual->now."\n";
+ }
+ Can't locate object method "now" via package "MyAppDB::Dual" at headshot.pl
+line 23.
+
+You could of course use 'dummy' in C<as> instead of 'now', or C<add_columns> to
+your Dual class for whatever you wanted to select from dual, but that's just
+silly, instead use C<get_column>
+
+ while (my $dual = $rs->next) {
+ print $dual->get_column('now')."\n";
+ }
+
+Or use C<cursor>
+
+ my $cursor = $rs->cursor;
+ while (my @vals = $cursor->next) {
+ print $vals[0]."\n";
+ }
+
+Or use L<DBIx::Class::ResultClass::HashRefInflator>
+
+ $rs->result_class('DBIx::Class::ResultClass::HashRefInflator');
+ while ( my $dual = $rs->next ) {
+ print $dual->{now}."\n";
+ }
+
+Here are some example C<select> conditions to illustrate the different syntax
+you could use for doing stuff like
+C<oracles.heavily(nested(functions_can('take', 'lots'), OF), 'args')>
+
+ # get a sequence value
+ select => [ 'A_SEQ.nextval' ],
+
+ # get create table sql
+ select => [ { 'dbms_metadata.get_ddl' => [ "'TABLE'", "'ARTIST'" ]} ],
+
+ # get a random num between 0 and 100
+ select => [ { "trunc" => [ { "dbms_random.value" => [0,100] } ]} ],
+
+ # what year is it?
+ select => [ { 'extract' => [ \'year from sysdate' ] } ],
+
+ # do some math
+ select => [ {'round' => [{'cos' => [ \'180 * 3.14159265359/180' ]}]}],
+
+ # which day of the week were you born on?
+ select => [{'to_char' => [{'to_date' => [ "'25-DEC-1980'", "'dd-mon-yyyy'"
+]}, "'day'"]}],
+
+ # select 16 rows from dual
+ select => [ "'hello'" ],
+ as => [ 'world' ],
+ group_by => [ 'cube( 1, 2, 3, 4 )' ],
+
+
+
=head2 Adding Indexes And Functions To Your SQL
Often you will want indexes on columns on your table to speed up searching. To