X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultSet.pm;h=f700f7a922beee455a6a3b13532600c66a8c16c3;hb=160dd90a19c870269d74303bcb406d7632e2780f;hp=33c84d387f4099c21be93b584a84db0f0629a4d0;hpb=921b75f00f5ef23bdfbe3c72ae617e94e4040137;p=dbsrgits%2FDBIx-Class-Historic.git
diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index 33c84d3..f700f7a 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
@@ -337,6 +341,9 @@ 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.
+In addition to C, L recognizes and applies standard
+L in the same way as L does.
+
Note: If your query does not return only one row, a warning is generated:
Query returned more than one row
@@ -569,19 +576,29 @@ 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
-Can optionally take an additional condition B - this is a fast-code-path
-method; if you need to add extra joins or similar call L and then
-L without a condition on the L returned from
-that.
+=item B
-B: As of 0.08100, this method assumes that the query returns only one
-row. If more than one row is returned, you will receive a warning:
+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:
Query returned more than one row
-In this case, you should be using L or L instead.
+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
@@ -1279,11 +1296,26 @@ 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);
@@ -1498,7 +1530,7 @@ sub page {
=item Arguments: \%vals
-=item Return Value: $object
+=item Return Value: $rowobject
=back
@@ -1515,17 +1547,40 @@ sub new_result {
my ($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
@@ -1534,6 +1589,20 @@ 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.
@@ -1598,16 +1667,33 @@ 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 {
@@ -1696,13 +1782,14 @@ 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({
@@ -1723,6 +1810,18 @@ 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.
@@ -1742,11 +1841,11 @@ 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
@@ -1766,6 +1865,14 @@ For example:
{ key => 'cd_artist_title' }
);
+ $cd->cd_to_producer->update_or_create({
+ producer => $producer,
+ name => 'harry',
+ }, {
+ key => 'primary,
+ });
+
+
If no C is specified, it searches on all unique constraints defined on the
source, including the primary key.
@@ -1774,6 +1881,12 @@ If the C is specified as C, it searches only on the primary key.
See also L and L. For information on how to declare
unique constraints, see L.
+B: C is probably not what you want when
+looking for a row in a table that uses primary keys supplied by the
+database, unless you actually have a key value. Passing in a primary
+key column with a value of I will cause L to attempt to
+search for a row with a value of I.
+
=cut
sub update_or_create {
@@ -1802,6 +1915,9 @@ sub update_or_create {
Gets the contents of the cache for the resultset, if the cache is set.
+The cache is populated either by using the L attribute to
+L or by calling L.
+
=cut
sub get_cache {
@@ -1823,6 +1939,9 @@ of objects of the same class as those produced by the resultset. Note that
if the cache is set the resultset will return the cached objects rather
than re-querying the database even if the cache attr is not set.
+The contents of the cache can also be populated by using the
+L attribute to L.
+
=cut
sub set_cache {
@@ -2118,44 +2237,44 @@ sub _calculate_score {
}
sub _merge_attr {
- my ($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 {
@@ -2208,6 +2327,10 @@ L) you will need to do C<\'year DESC' >
specify an order. (The scalar ref causes it to be passed as raw sql to the DB,
so you will need to manually quote things as appropriate.)
+If your L version supports it (>=1.50), you can also use
+C<{-desc => 'year'}>, which takes care of the quoting for you. This is the
+recommended syntax.
+
=head2 columns
=over 4
@@ -2435,13 +2558,27 @@ 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