X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FManual%2FFAQ.pod;h=464040dad4b23a031fdb765a758051fb5e9b458e;hb=6aafb6a62ca556f2d34cab164425a401b7ffe8cd;hp=4a5d7ba0896d2238cfa24d4c56363565ed87fb13;hpb=0a7ed5b00ca9ee32e7c2efa7d3481e9619252cf3;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Manual/FAQ.pod b/lib/DBIx/Class/Manual/FAQ.pod
index 4a5d7ba..464040d 100644
--- a/lib/DBIx/Class/Manual/FAQ.pod
+++ b/lib/DBIx/Class/Manual/FAQ.pod
@@ -126,7 +126,7 @@ allow you to supply a hashref containing the condition across which
 the tables are to be joined. The condition may contain as many fields
 as you like. See L<DBIx::Class::Relationship::Base>.
 
-=item .. define a relatiopnship across an intermediate table? (many-to-many)
+=item .. define a relationship across an intermediate table? (many-to-many)
 
 Read the documentation on L<DBIx::Class::Relationship/many_to_many>.
 
@@ -182,15 +182,9 @@ attribute. See L<DBIx::Class::ResultSet/order_by>.
 
 =item .. sort my results based on fields I've aliased using C<as>?
 
-You don't. You'll need to supply the same functions/expressions to
-C<order_by>, as you did to C<select>.
-
-To get "fieldname AS alias" in your SQL, you'll need to supply a
-literal chunk of SQL in your C<select> attribute, such as:
-
- ->search({}, { select => [ \'now() AS currenttime'] })
-
-Then you can use the alias in your C<order_by> attribute.
+You didn't alias anything, since L<as|DBIx::Class::ResultSet/as>
+B<has nothing to do> with the produced SQL. See
+L<DBIx::Class::ResultSet/select> for details.
 
 =item .. group the results of my search?
 
@@ -199,15 +193,7 @@ attribute, see L<DBIx::Class::ResultSet/group_by>.
 
 =item .. group my results based on fields I've aliased using C<as>?
 
-You don't. You'll need to supply the same functions/expressions to
-C<group_by>, as you did to C<select>.
-
-To get "fieldname AS alias" in your SQL, you'll need to supply a
-literal chunk of SQL in your C<select> attribute, such as:
-
- ->search({}, { select => [ \'now() AS currenttime'] })
-
-Then you can use the alias in your C<group_by> attribute.
+You don't. See the explanation on ordering by an alias above.
 
 =item .. filter the results of my search?
 
@@ -371,6 +357,9 @@ 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
@@ -430,6 +419,38 @@ 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
@@ -517,6 +538,65 @@ 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
@@ -547,7 +627,7 @@ 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