X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultSet.pm;h=bd615d3f35c13f029ec90aa3f074b112dec6c10e;hb=27252a4a98791c2fcf13693cfbb9f8c44f5e585b;hp=b4f33ce1eff6f4633a21376ae149393431e149a9;hpb=6264db979f72eae9a0de1b314812fbf5a6fc058f;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm index b4f33ce..bd615d3 100644 --- a/lib/DBIx/Class/ResultSet.pm +++ b/lib/DBIx/Class/ResultSet.pm @@ -12,6 +12,7 @@ use Storable; use DBIx::Class::ResultSetColumn; use DBIx::Class::ResultSourceHandle; use List::Util (); +use Scalar::Util (); use base qw/DBIx::Class/; __PACKAGE__->mk_group_accessors('simple' => qw/result_class _source_handle/); @@ -22,8 +23,8 @@ DBIx::Class::ResultSet - Responsible for fetching and creating resultset. =head1 SYNOPSIS - my $rs = $schema->resultset('User')->search(registered => 1); - my @rows = $schema->resultset('CD')->search(year => 2005); + my $rs = $schema->resultset('User')->search({ registered => 1 }); + my @rows = $schema->resultset('CD')->search({ year => 2005 })->all(); =head1 DESCRIPTION @@ -53,7 +54,10 @@ In the examples below, the following table classes are used: =head1 OVERLOADING -If a resultset is used as a number it returns the C. However, if it is used as a boolean it is always true. So if you want to check if a result set has any results use C. C will always be true. +If a resultset is used in a numeric context it returns the L. +However, if it is used in a booleand context it is always true. So if +you want to check if a resultset has any results use C. +C will always be true. =head1 METHODS @@ -196,7 +200,7 @@ sub search_rs { my $new_attrs = { %{$our_attrs}, %{$attrs} }; # merge new attrs into inherited - foreach my $key (qw/join prefetch/) { + foreach my $key (qw/join prefetch +select +as/) { next unless exists $attrs->{$key}; $new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key}); } @@ -303,7 +307,7 @@ sub search_literal { =item Arguments: @values | \%cols, \%attrs? -=item Return Value: $row_object +=item Return Value: $row_object | undef =back @@ -332,11 +336,15 @@ Additionally, you can specify the columns explicitly by name: If the C is specified as C, it searches only on the primary key. If no C is specified, it searches on all unique constraints defined on the -source, including the primary key. +source for which column data is provided, including the primary key. If your table does not have a primary key, you B provide a value for the C attribute matching one of the unique constraints on the source. +Note: If your query does not return only one row, a warning is generated: + + Query returned more than one row + See also L and L. For information on how to declare unique constraints, see L. @@ -388,25 +396,46 @@ sub find { @{$input_query}{@keys} = values %related; } - my @unique_queries = $self->_unique_queries($input_query, $attrs); # Build the final query: Default to the disjunction of the unique queries, # but allow the input query in case the ResultSet defines the query or the # user is abusing find my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias}; - my $query = @unique_queries - ? [ map { $self->_add_alias($_, $alias) } @unique_queries ] - : $self->_add_alias($input_query, $alias); + my $query; + if (exists $attrs->{key}) { + my @unique_cols = $self->result_source->unique_constraint_columns($attrs->{key}); + my $unique_query = $self->_build_unique_query($input_query, \@unique_cols); + $query = $self->_add_alias($unique_query, $alias); + } + else { + my @unique_queries = $self->_unique_queries($input_query, $attrs); + $query = @unique_queries + ? [ map { $self->_add_alias($_, $alias) } @unique_queries ] + : $self->_add_alias($input_query, $alias); + } # Run the query if (keys %$attrs) { my $rs = $self->search($query, $attrs); - return keys %{$rs->_resolved_attrs->{collapse}} ? $rs->next : $rs->single; + if (keys %{$rs->_resolved_attrs->{collapse}}) { + my $row = $rs->next; + carp "Query returned more than one row" if $rs->next; + return $row; + } + else { + return $rs->single; + } } else { - return keys %{$self->_resolved_attrs->{collapse}} - ? $self->search($query)->next - : $self->single($query); + if (keys %{$self->_resolved_attrs->{collapse}}) { + my $rs = $self->search($query); + my $row = $rs->next; + carp "Query returned more than one row" if $rs->next; + return $row; + } + else { + return $self->single($query); + } } } @@ -544,11 +573,29 @@ sub cursor { my $cd = $schema->resultset('CD')->single({ year => 2001 }); Inflates the first result without creating a cursor if the resultset has -any records in it; if not returns nothing. Used by L as an optimisation. +any records in it; if not returns nothing. Used by L as a lean version of +L. + +While this method can take an optional search condition (just like L) +being a fast-code-path it does not recognize search attributes. If you need to +add extra joins or similar, call L and then chain-call L on the +L returned. + +=over + +=item B + +As of 0.08100, this method enforces the assumption that the preceeding +query returns only one row. If more than one row is returned, you will receive +a warning: -Can optionally take an additional condition *only* - this is a fast-code-path -method; if you need to add extra joins or similar call ->search and then -->single without a condition on the $rs returned from that. + Query returned more than one row + +In this case, you should be using L or L instead, or if you really +know what you are doing, use the L attribute to explicitly limit the size +of the resultset. + +=back =cut @@ -1246,11 +1293,26 @@ Deletes the contents of the resultset from its result source. Note that this will not run DBIC cascade triggers. See L if you need triggers to run. See also L. +delete may not generate correct SQL for a query with joins or a resultset +chained from a related resultset. In this case it will generate a warning:- + + WARNING! Currently $rs->delete() does not generate proper SQL on + joined resultsets, and may delete rows well outside of the contents + of $rs. Use at your own risk + +In these cases you may find that delete_all is more appropriate, or you +need to respecify your query in a way that can be expressed without a join. + =cut sub delete { my ($self) = @_; - + $self->throw_exception("Delete should not be passed any arguments") + if $_[1]; + carp( 'WARNING! Currently $rs->delete() does not generate proper SQL' + . ' on joined resultsets, and may delete rows well outside of the' + . ' contents of $rs. Use at your own risk' ) + if ( $self->{attrs}{seen_join} ); my $cond = $self->_cond_for_update_delete; $self->result_source->storage->delete($self->result_source, $cond); @@ -1465,7 +1527,7 @@ sub page { =item Arguments: \%vals -=item Return Value: $object +=item Return Value: $rowobject =back @@ -1482,17 +1544,40 @@ sub new_result { my ($self, $values) = @_; $self->throw_exception( "new_result needs a hash" ) unless (ref $values eq 'HASH'); - $self->throw_exception( - "Can't abstract implicit construct, condition not a hash" - ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH')); + my %new; my $alias = $self->{attrs}{alias}; - my $collapsed_cond = $self->{cond} ? $self->_collapse_cond($self->{cond}) : {}; - # precendence must be given to passed values over values inherited from the cond, - # so the order here is important. - my %new = ( - %{ $self->_remove_alias($collapsed_cond, $alias) }, + if ( + defined $self->{cond} + && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION + ) { + %new = %{$self->{attrs}{related_objects}}; + } else { + $self->throw_exception( + "Can't abstract implicit construct, condition not a hash" + ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH')); + + my $collapsed_cond = ( + $self->{cond} + ? $self->_collapse_cond($self->{cond}) + : {} + ); + + # precendence must be given to passed values over values inherited from + # the cond, so the order here is important. + my %implied = %{$self->_remove_alias($collapsed_cond, $alias)}; + while( my($col,$value) = each %implied ){ + if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){ + $new{$col} = $value->{'='}; + next; + } + $new{$col} = $value if $self->_is_deterministic_value($value); + } + } + + %new = ( + %new, %{ $self->_remove_alias($values, $alias) }, -source_handle => $self->_source_handle, -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED @@ -1501,6 +1586,20 @@ sub new_result { return $self->result_class->new(\%new); } +# _is_deterministic_value +# +# Make an effor to strip non-deterministic values from the condition, +# to make sure new_result chokes less + +sub _is_deterministic_value { + my $self = shift; + my $value = shift; + my $ref_type = ref $value; + return 1 if $ref_type eq '' || $ref_type eq 'SCALAR'; + return 1 if Scalar::Util::blessed($value); + return 0; +} + # _collapse_cond # # Recursively collapse the condition. @@ -1565,16 +1664,33 @@ sub _remove_alias { =item Arguments: \%vals, \%attrs? -=item Return Value: $object +=item Return Value: $rowobject =back -Find an existing record from this resultset. If none exists, instantiate a new -result object and return it. The object will not be saved into your storage + my $artist = $schema->resultset('Artist')->find_or_new( + { artist => 'fred' }, { key => 'artists' }); + + $cd->cd_to_producer->find_or_new({ producer => $producer }, + { key => 'primary }); + +Find an existing record from this resultset, based on it's primary +key, or a unique constraint. If none exists, instantiate a new result +object and return it. The object will not be saved into your storage until you call L on it. +You most likely want this method when looking for existing rows using +a unique constraint that is not the primary key, or looking for +related rows. + If you want objects to be saved immediately, use L instead. +B: C is probably not what you want when creating a +new row in a table that uses primary keys supplied by the +database. Passing in a primary key column with a value of I +will cause L to attempt to search for a row with a value of +I. + =cut sub find_or_new { @@ -1663,13 +1779,14 @@ sub create { =item Arguments: \%vals, \%attrs? -=item Return Value: $object +=item Return Value: $rowobject =back - $class->find_or_create({ key => $val, ... }); + $cd->cd_to_producer->find_or_create({ producer => $producer }, + { key => 'primary }); -Tries to find a record based on its primary key or unique constraint; if none +Tries to find a record based on its primary key or unique constraints; if none is found, creates one and returns that instead. my $cd = $schema->resultset('CD')->find_or_create({ @@ -1690,6 +1807,18 @@ constraint. For example: { key => 'cd_artist_title' } ); +B: Because find_or_create() reads from the database and then +possibly inserts based on the result, this method is subject to a race +condition. Another process could create a record in the table after +the find has completed and before the create has started. To avoid +this problem, use find_or_create() inside a transaction. + +B: C is probably not what you want when creating +a new row in a table that uses primary keys supplied by the +database. Passing in a primary key column with a value of I +will cause L to attempt to search for a row with a value of +I. + See also L and L. For information on how to declare unique constraints, see L. @@ -1709,11 +1838,11 @@ sub find_or_create { =item Arguments: \%col_values, { key => $unique_constraint }? -=item Return Value: $object +=item Return Value: $rowobject =back - $class->update_or_create({ col => $val, ... }); + $resultset->update_or_create({ col => $val, ... }); First, searches for an existing row matching one of the unique constraints (including the primary key) on the source of this resultset. If a row is @@ -1733,6 +1862,14 @@ For example: { key => 'cd_artist_title' } ); + $cd->cd_to_producer->update_or_create({ + producer => $producer, + name => 'harry', + }, { + key => 'primary, + }); + + If no C is specified, it searches on all unique constraints defined on the source, including the primary key. @@ -1741,6 +1878,12 @@ If the C is specified as C, it searches only on the primary key. See also L and L. For information on how to declare unique constraints, see L. +B: C is probably not what you want when +looking for a row in a table that uses primary keys supplied by the +database, unless you actually have a key value. Passing in a primary +key column with a value of I will cause L to attempt to +search for a row with a value of I. + =cut sub update_or_create { @@ -1769,6 +1912,9 @@ sub update_or_create { Gets the contents of the cache for the resultset, if the cache is set. +The cache is populated either by using the L attribute to +L or by calling L. + =cut sub get_cache { @@ -1790,6 +1936,9 @@ of objects of the same class as those produced by the resultset. Note that if the cache is set the resultset will return the cached objects rather than re-querying the database even if the cache attr is not set. +The contents of the cache can also be populated by using the +L attribute to L. + =cut sub set_cache { @@ -2085,44 +2234,44 @@ sub _calculate_score { } sub _merge_attr { - my ($self, $a, $b) = @_; + my ($self, $orig, $import) = @_; - return $b unless defined($a); - return $a unless defined($b); + return $import unless defined($orig); + return $orig unless defined($import); - $a = $self->_rollout_attr($a); - $b = $self->_rollout_attr($b); + $orig = $self->_rollout_attr($orig); + $import = $self->_rollout_attr($import); my $seen_keys; - foreach my $b_element ( @{$b} ) { - # find best candidate from $a to merge $b_element into + foreach my $import_element ( @{$import} ) { + # find best candidate from $orig to merge $b_element into my $best_candidate = { position => undef, score => 0 }; my $position = 0; - foreach my $a_element ( @{$a} ) { - my $score = $self->_calculate_score( $a_element, $b_element ); + foreach my $orig_element ( @{$orig} ) { + my $score = $self->_calculate_score( $orig_element, $import_element ); if ($score > $best_candidate->{score}) { $best_candidate->{position} = $position; $best_candidate->{score} = $score; } $position++; } - my ($b_key) = ( ref $b_element eq 'HASH' ) ? keys %{$b_element} : ($b_element); + my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element); - if ($best_candidate->{score} == 0 || exists $seen_keys->{$b_key}) { - push( @{$a}, $b_element ); + if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) { + push( @{$orig}, $import_element ); } else { - my $a_best = $a->[$best_candidate->{position}]; - # merge a_best and b_element together and replace original with merged - if (ref $a_best ne 'HASH') { - $a->[$best_candidate->{position}] = $b_element; - } elsif (ref $b_element eq 'HASH') { - my ($key) = keys %{$a_best}; - $a->[$best_candidate->{position}] = { $key => $self->_merge_attr($a_best->{$key}, $b_element->{$key}) }; + my $orig_best = $orig->[$best_candidate->{position}]; + # merge orig_best and b_element together and replace original with merged + if (ref $orig_best ne 'HASH') { + $orig->[$best_candidate->{position}] = $import_element; + } elsif (ref $import_element eq 'HASH') { + my ($key) = keys %{$orig_best}; + $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) }; } } - $seen_keys->{$b_key} = 1; # don't merge the same key twice + $seen_keys->{$import_key} = 1; # don't merge the same key twice } - return $a; + return $orig; } sub result_source { @@ -2402,13 +2551,27 @@ C or C relationships, which saves us two SQL statements in this case. Simple prefetches will be joined automatically, so there is no need -for a C attribute in the above search. If you're prefetching to -depth (e.g. { cd => { artist => 'label' } or similar), you'll need to -specify the join as well. +for a C attribute in the above search. C can be used with the following relationship types: C, C (or if you're using C, any relationship declared -with an accessor type of 'single' or 'filter'). +with an accessor type of 'single' or 'filter'). A more complex example that +prefetches an artists cds, the tracks on those cds, and the tags associted +with that artist is given below (assuming many-to-many from artists to tags): + + my $rs = $schema->resultset('Artist')->search( + undef, + { + prefetch => [ + { cds => 'tracks' }, + { artist_tags => 'tags' } + ] + } + ); + + +B If you specify a C attribute, the C and C