The first argument to C<search> is a hashref of accessor names and
values to filter them by, for example:
- ->search({'created_time' => { '>=', '2006-06-01 00:00:00'} })
+ ->search({'created_time' => { '>=', '2006-06-01 00:00:00' } })
Note that to use a function here you need to make the whole value into
a scalar reference:
- ->search({'created_time' => \'>= yesterday() })
+ ->search({'created_time' => \'>= yesterday()' })
=item .. search in several tables simultaneously?
your search, for example when searching in the Books table for all the
books by the author "Fred Bloggs":
- ->search({'authors.name' => 'Fred Bloggs'}, { join => 'authors'})
+ ->search({'authors.name' => 'Fred Bloggs'}, { join => 'authors' })
The type of join created in your SQL depends on the type of
relationship between the two tables, see L<DBIx::Class::Relationship>
=over 4
-=item .. fetch as much data as possible in as few select calls as possible? (prefetch)
+=item .. fetch as much data as possible in as few select calls as possible?
See the prefetch examples in the L<Cookbook|DBIx::Class::Manual::Cookbook>.
+=item .. fetch a whole column of data instead of a row?
+
+Call C<get_column> on a L<DBIx::Class::ResultSet>, this returns a
+L<DBIx::Class::ResultSetColumn>, see it's documentation and the
+L<Cookbook|DBIx::Class::Manual::Cookbook> for details.
+
+=item .. fetch a formatted column?
+
+In your table schema class, create a "private" column accessor with:
+
+ __PACKAGE__->add_columns(my_common => { accessor => '_hidden_my_column' });
+
+Then, in the same class, implement a subroutine called "my_column" that
+fetches the real value and does the formatting you want.
+
+See the Cookbook for more details.
+
+=item .. fetch a single (or topmost) row?
+
+Sometimes you many only want a single record back from a search. A quick
+way to get that single row is to first run your search as usual:
+
+ ->search->(undef, { order_by => "id DESC" })
+
+Then call L<DBIx::Class::ResultSet/slice> and ask it only to return 1 row:
+
+ ->slice(0,1)
+
+These two calls can be combined into a single statement:
+
+ ->search->(undef, { order_by => "id DESC" })->slice(0,1)
+
+Why slice instead of L<DBIx::Class::ResultSet/first> or L<DBIx::Class::ResultSet/single>?
+If supported by the database, slice will use LIMIT/OFFSET to hint to the database that we
+really only need one row. This can result in a significant speed improvement.
+
=back
=head2 Inserting and updating data
To stop the column name from being quoted, you'll need to supply a
scalar reference:
- ->update({ somecolumn => '\othercolumn'})
+ ->update({ somecolumn => \'othercolumn' })
+
+=item .. store JSON/YAML in a column and have it deflate/inflate automatically?
+
+You can use L<DBIx::Class::InflateColumn> to accomplish YAML/JSON storage transparently.
+
+If you want to use JSON, then in your table schema class, do the following:
+
+ use JSON;
+
+ __PACKAGE__->add_columns(qw/ ... my_column ../)
+ __PACKAGE__->inflate_column('my_column', {
+ inflate => sub { jsonToObj(shift) },
+ deflate => sub { objToJson(shift) },
+ });
+
+For YAML, in your table schema class, do the following:
+
+ use YAML;
+
+ __PACKAGE__->add_columns(qw/ ... my_column ../)
+ __PACKAGE__->inflate_column('my_column', {
+ inflate => sub { YAML::Load(shift) },
+ deflate => sub { YAML::Dump(shift) },
+ });
+
+This technique is an easy way to store supplemental unstructured data in a table. Be
+careful not to overuse this capability, however. If you find yourself depending more
+and more on some data within the inflated column, then it may be time to factor that
+data out.
=back
=item See the SQL statements my code is producing?
-Turn on debugging! See L<DBIx::Class::Storage::DBI> for details of how
+Turn on debugging! See L<DBIx::Class::Storage> for details of how
to turn on debugging in the environment, pass your own filehandle to
save debug to, or create your own callback.
you ask the resultset for an actual row object.
=back
+
+=head2 Notes for CDBI users
+
+=over 4
+
+=item Is there a way to make an object auto-stringify itself as a
+particular column or group of columns (a-la cdbi Stringfy column
+group, or stringify_self method) ?
+
+See L<Cookbook/Stringification>
+
+=back