undo that attributes merge stuff

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / ResultSet.pm

diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index fae8f01..b7ba496 100644 (file)
--- a/lib/DBIx/Class/ResultSet.pm
+++ b/lib/DBIx/Class/ResultSet.pm
@@ -1315,9 +1315,12 @@ sub _count_subq_rs {
 sub _switch_to_inner_join_if_needed {
   my ($self, $from, $alias) = @_;
 
+  # subqueries and other oddness is naturally not supported
   return $from if (
     ref $from ne 'ARRAY'
       ||
+    @$from <= 1
+      ||
     ref $from->[0] ne 'HASH'
       ||
     ! $from->[0]{-alias}
@@ -1325,10 +1328,6 @@ sub _switch_to_inner_join_if_needed {
     $from->[0]{-alias} eq $alias
   );
 
-  # this would be the case with a subquery - we'll never find
-  # the target as it is not in the parseable part of {from}
-  return $from if @$from == 1;
-
   my $switch_branch;
   JOINSCAN:
   for my $j (@{$from}[1 .. $#$from]) {
@@ -2233,12 +2232,15 @@ store. If the appropriate relationships are set up, foreign key fields
 can also be passed an object representing the foreign row, and the
 value will be set to its primary key.
 
-To create related objects, pass a hashref for the value if the related
-item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
-and use the name of the relationship as the key. (NOT the name of the field,
-necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
-of hashrefs containing the data for each of the rows to create in the foreign
-tables, again using the relationship name as the key.
+To create related objects, pass a hashref of related-object column values
+B<keyed on the relationship name>. If the relationship is of type C<multi>
+(L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
+The process will correctly identify columns holding foreign keys, and will
+transparrently populate them from the keys of the corresponding relation.
+This can be applied recursively, and will work correctly for a structure
+with an arbitrary depth and width, as long as the relationships actually
+exists and the correct column data has been supplied.
+
 
 Instead of hashrefs of plain related data (key/value pairs), you may
 also pass new or inserted objects. New objects (not inserted yet, see
@@ -3088,10 +3090,15 @@ These are in no particular order:
 
 =back
 
-Which column(s) to order the results by. If a single column name, or
-an arrayref of names is supplied, the argument is passed through
-directly to SQL. The hashref syntax allows for connection-agnostic
-specification of ordering direction:
+Which column(s) to order the results by. 
+
+[The full list of suitable values is documented in
+L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
+common options.]
+
+If a single column name, or an arrayref of names is supplied, the
+argument is passed through directly to SQL. The hashref syntax allows
+for connection-agnostic specification of ordering direction:
 
  For descending order:
 
@@ -3370,6 +3377,42 @@ with that artist is given below (assuming many-to-many from artists to tags):
 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
 attributes will be ignored.
 
+B<CAVEATs>: Prefetch does a lot of deep magic. As such, it may not behave
+exactly as you might expect.
+
+=over 4
+
+=item * 
+
+Prefetch uses the L</cache> to populate the prefetched relationships. This
+may or may not be what you want.
+
+=item * 
+
+If you specify a condition on a prefetched relationship, ONLY those
+rows that match the prefetched condition will be fetched into that relationship.
+This means that adding prefetch to a search() B<may alter> what is returned by
+traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
+
+  my $artist_rs = $schema->resultset('Artist')->search({
+      'cds.year' => 2008,
+  }, {
+      join => 'cds',
+  });
+
+  my $count = $artist_rs->first->cds->count;
+
+  my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
+
+  my $prefetch_count = $artist_rs_prefetch->first->cds->count;
+
+  cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
+
+that cmp_ok() may or may not pass depending on the datasets involved. This
+behavior may or may not survive the 0.09 transition.
+
+=back
+
 =head2 page
 
 =over 4