fix typo per nuba on irc

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / Manual / FAQ.pod

diff --git a/lib/DBIx/Class/Manual/FAQ.pod b/lib/DBIx/Class/Manual/FAQ.pod
index cf75fd2..dbc239f 100644 (file)
--- a/lib/DBIx/Class/Manual/FAQ.pod
+++ b/lib/DBIx/Class/Manual/FAQ.pod
@@ -247,7 +247,13 @@ documentation for details.
 
 To use an SQL function on the left hand side of a comparison:
 
- ->search({ -nest => \[ 'YEAR(date_of_birth) = ?', [ dummy => 1979 ] ] });
+ ->search({ -nest => \[ 'YEAR(date_of_birth) = ?', [ plain_value => 1979 ] ] });
+
+Note: the C<plain_value> string in the C<< [ plain_value => 1979 ] >> part
+should be either the same as the name of the column (do this if the type of the
+return value of the function is the same as the type of the column) or
+otherwise it's essentially a dummy string currently (use C<plain_value> as a
+habit). It is used by L<DBIx::Class> to handle special column types.
 
 Or, if you have quoting off:
 
@@ -365,6 +371,9 @@ C<column_info> supplied with C<add_columns>.
 
 =item .. insert many rows of data efficiently?
 
+The C<populate> method in L<DBIx::Class::ResultSet> provides
+efficient bulk inserts.
+
 =item .. update a collection of rows at the same time?
 
 Create a resultset using a search, to filter the rows of data you
@@ -424,6 +433,38 @@ data out.
 
 =back
 
+=head2 Custom methods in Result classes
+
+You can add custom methods that do arbitrary things, even to unrelated tables. 
+For example, to provide a C<< $book->foo() >> method which searches the 
+cd table, you'd could add this to Book.pm:
+
+  sub foo {
+    my ($self, $col_data) = @_;
+    return $self->result_source->schema->resultset('cd')->search($col_data);
+  }
+
+And invoke that on any Book Result object like so:
+
+  my $rs = $book->foo({ title => 'Down to Earth' });
+
+When two tables ARE related, L<DBIx::Class::Relationship::Base> provides many
+methods to find or create data in related tables for you. But if you want to
+write your own methods, you can.
+
+For example, to provide a C<< $book->foo() >> method to manually implement
+what create_related() from L<DBIx::Class::Relationship::Base> does, you could 
+add this to Book.pm:
+
+  sub foo {
+    my ($self, $relname, $col_data) = @_;
+    return $self->related_resultset($relname)->create($col_data);
+  }
+
+Invoked like this:
+
+  my $author = $book->foo('author', { name => 'Fred' });
+
 =head2 Misc
 
 =over 4
@@ -511,6 +552,65 @@ You can reduce the overhead of object creation within L<DBIx::Class>
 using the tips in L<DBIx::Class::Manual::Cookbook/"Skip row object creation for faster results">
 and L<DBIx::Class::Manual::Cookbook/"Get raw data for blindingly fast results">
 
+=item How do I override a run time method (e.g. a relationship accessor)?
+
+If you need access to the original accessor, then you must "wrap around" the original method.
+You can do that either with L<Moose::Manual::MethodModifiers> or L<Class::Method::Modifiers>.
+The code example works for both modules:
+
+    package Your::Schema::Group;
+    use Class::Method::Modifiers;
+    
+    # ... declare columns ...
+    
+    __PACKAGE__->has_many('group_servers', 'Your::Schema::GroupServer', 'group_id');
+    __PACKAGE__->many_to_many('servers', 'group_servers', 'server');
+    
+    # if the server group is a "super group", then return all servers
+    # otherwise return only servers that belongs to the given group
+    around 'servers' => sub {
+        my $orig = shift;
+        my $self = shift;
+
+        return $self->$orig(@_) unless $self->is_super_group;
+        return $self->result_source->schema->resultset('Server')->all;
+    };
+
+If you just want to override the original method, and don't care about the data
+from the original accessor, then you have two options. Either use
+L<Method::Signatures::Simple> that does most of the work for you, or do
+it the "dirty way".
+
+L<Method::Signatures::Simple> way:
+
+    package Your::Schema::Group;
+    use Method::Signatures::Simple;
+    
+    # ... declare columns ...
+    
+    __PACKAGE__->has_many('group_servers', 'Your::Schema::GroupServer', 'group_id');
+    __PACKAGE__->many_to_many('servers', 'group_servers', 'server');
+    
+    # The method keyword automatically injects the annoying my $self = shift; for you.
+    method servers {
+        return $self->result_source->schema->resultset('Server')->search({ ... });
+    }
+
+The dirty way:
+
+    package Your::Schema::Group;
+    use Sub::Name;
+    
+    # ... declare columns ...
+    
+    __PACKAGE__->has_many('group_servers', 'Your::Schema::GroupServer', 'group_id');
+    __PACKAGE__->many_to_many('servers', 'group_servers', 'server');
+    
+    *servers = subname servers => sub {
+        my $self = shift;
+        return $self->result_source->schema->resultset('Server')->search({ ... });
+    };
+    
 =back
 
 =head2 Notes for CDBI users
@@ -541,7 +641,7 @@ Likely you have/had two copies of postgresql installed simultaneously, the
 second one will use a default port of 5433, while L<DBD::Pg> is compiled with a
 default port of 5432.
 
-You can chance the port setting in C<postgresql.conf>.
+You can change the port setting in C<postgresql.conf>.
 
 =item I've lost or forgotten my mysql password