use strict;
use warnings;
-use overload
- '0+' => "count",
- 'bool' => "_bool",
- fallback => 1;
+use base qw/DBIx::Class/;
use Carp::Clan qw/^DBIx::Class/;
+use DBIx::Class::Exception;
use Data::Page;
use Storable;
use DBIx::Class::ResultSetColumn;
use DBIx::Class::ResultSourceHandle;
use List::Util ();
-use Scalar::Util ();
-use base qw/DBIx::Class/;
+use Scalar::Util qw/blessed weaken/;
+use Try::Tiny;
+use namespace::clean;
+
+use overload
+ '0+' => "count",
+ 'bool' => "_bool",
+ fallback => 1;
__PACKAGE__->mk_group_accessors('simple' => qw/_result_class _source_handle/);
=head1 SYNOPSIS
my $users_rs = $schema->resultset('User');
+ while( $user = $users_rs->next) {
+ print $user->username;
+ }
+
my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
The query that the ResultSet represents is B<only> executed against
the database when these methods are called:
-L</find> L</next> L</all> L</first> L</single> L</count>
+L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
+
+If a resultset is used in a numeric context it returns the L</count>.
+However, if it is used in a boolean context it is B<always> true. So if
+you want to check if a resultset has any results, you must use C<if $rs
+!= 0>.
=head1 EXAMPLES
L</join>, L</prefetch>, L</+select>, L</+as> attributes are merged
into the existing ones from the original resultset.
-The L</where>, L</having> attribute, and any search conditions are
+The L</where> and L</having> attributes, and any search conditions, are
merged with an SQL C<AND> to the existing condition from the original
resultset.
See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
-=head1 OVERLOADING
-
-If a resultset is used in a numeric context it returns the L</count>.
-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<if $rs != 0>.
-C<if $rs> will always be true.
-
=head1 METHODS
=head2 new
my $self = {
_source_handle => $source,
cond => $attrs->{where},
- count => undef,
pager => undef,
attrs => $attrs
};
$rows = $self->get_cache;
}
+ # reset the selector list
+ if (List::Util::first { exists $attrs->{$_} } qw{columns select as}) {
+ delete @{$our_attrs}{qw{select as columns +select +as +columns include_columns}};
+ }
+
my $new_attrs = { %{$our_attrs}, %{$attrs} };
# merge new attrs into inherited
- foreach my $key (qw/join prefetch +select +as bind/) {
+ foreach my $key (qw/join prefetch +select +as +columns include_columns bind/) {
next unless exists $attrs->{$key};
$new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
}
}
my $rs = (ref $self)->new($self->result_source, $new_attrs);
- if ($rows) {
- $rs->set_cache($rows);
- }
+
+ $rs->set_cache($rows) if ($rows);
+
return $rs;
}
my $unique_query = $self->_build_unique_query($input_query, \@unique_cols);
$query = $self->_add_alias($unique_query, $alias);
}
+ elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
+ # This means that we got here after a merger of relationship conditions
+ # in ::Relationship::Base::search_related (the row method), and furthermore
+ # the relationship is of the 'single' type. This means that the condition
+ # provided by the relationship (already attached to $self) is sufficient,
+ # as there can be only one row in the database that would satisfy the
+ # relationship
+ }
else {
my @unique_queries = $self->_unique_queries($input_query, $attrs);
$query = @unique_queries
: $self->_add_alias($input_query, $alias);
}
- # Run the query
- if (keys %$attrs) {
- my $rs = $self->search($query, $attrs);
- if (keys %{$rs->_resolved_attrs->{collapse}}) {
- my $row = $rs->next;
- carp "Query returned more than one row" if $rs->next;
- return $row;
- }
- else {
- return $rs->single;
- }
+ # Run the query, passing the result_class since it should propagate for find
+ my $rs = $self->search ($query, {result_class => $self->result_class, %$attrs});
+ if (keys %{$rs->_resolved_attrs->{collapse}}) {
+ my $row = $rs->next;
+ carp "Query returned more than one row" if $rs->next;
+ return $row;
}
else {
- if (keys %{$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);
- }
+ return $rs->single;
}
}
my $where = $self->_collapse_cond($self->{attrs}{where} || {});
my $num_where = scalar keys %$where;
- my @unique_queries;
+ my (@unique_queries, %seen_column_combinations);
foreach my $name (@constraint_names) {
- my @unique_cols = $self->result_source->unique_constraint_columns($name);
- my $unique_query = $self->_build_unique_query($query, \@unique_cols);
+ my @constraint_cols = $self->result_source->unique_constraint_columns($name);
+
+ my $constraint_sig = join "\x00", sort @constraint_cols;
+ next if $seen_column_combinations{$constraint_sig}++;
+
+ my $unique_query = $self->_build_unique_query($query, \@constraint_cols);
- my $num_cols = scalar @unique_cols;
+ my $num_cols = scalar @constraint_cols;
my $num_query = scalar keys %$unique_query;
my $total = $num_query + $num_where;
=head2 search_related_rs
This method works exactly the same as search_related, except that
-it guarantees a restultset, even in list context.
+it guarantees a resultset, even in list context.
=cut
my ($self) = @_;
my $attrs = $self->_resolved_attrs_copy;
- $attrs->{_virtual_order_by} = $self->_gen_virtual_order;
return $self->{cursor}
||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
=item B<Note>
-As of 0.08100, this method enforces the assumption that the preceeding
+As of 0.08100, this method enforces the assumption that the preceding
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</first> or L</find> instead, or if you really
+In this case, you should be using L</next> or L</find> instead, or if you really
know what you are doing, use the L</rows> attribute to explicitly limit the size
of the resultset.
+This method will also throw an exception if it is called on a resultset prefetching
+has_many, as such a prefetch implies fetching multiple rows from the database in
+order to assemble the resulting object.
+
=back
=cut
}
my $attrs = $self->_resolved_attrs_copy;
- $attrs->{_virtual_order_by} = $self->_gen_virtual_order;
+
+ if (keys %{$attrs->{collapse}}) {
+ $self->throw_exception(
+ 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
+ );
+ }
if ($where) {
if (defined $attrs->{where}) {
return (@data ? ($self->_construct_object(@data))[0] : undef);
}
-# _gen_virtual_order
-#
-# This is a horrble hack, but seems like the best we can do at this point
-# Some limit emulations (Top) require an ordered resultset in order to
-# function at all. So supply a PK order to be used if necessary
-
-sub _gen_virtual_order {
- return [ shift->result_source->primary_columns ];
-}
# _is_unique_query
#
return $cache->[$self->{all_cache_position}++];
}
if ($self->{attrs}{cache}) {
+ delete $self->{pager};
$self->{all_cache_position} = 1;
return ($self->all)[0];
}
sub _construct_object {
my ($self, @row) = @_;
- my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
+
+ my $info = $self->_collapse_result($self->{_attrs}{as}, \@row)
+ or return ();
my @new = $self->result_class->inflate_result($self->result_source, @$info);
@new = $self->{_attrs}{record_filter}->(@new)
if exists $self->{_attrs}{record_filter};
# without having to contruct the full hash
if (keys %collapse) {
- my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
+ my %pri = map { ($_ => 1) } $self->result_source->_pri_cols;
foreach my $i (0 .. $#construct_as) {
next if defined($construct_as[$i][0]); # only self table
if (delete $pri{$construct_as[$i][1]}) {
sub result_class {
my ($self, $result_class) = @_;
if ($result_class) {
- $self->ensure_class_loaded($result_class);
+ unless (ref $result_class) { # don't fire this for an object
+ $self->ensure_class_loaded($result_class);
+ }
$self->_result_class($result_class);
+ # THIS LINE WOULD BE A BUG - this accessor specifically exists to
+ # permit the user to set result class on one result set only; it only
+ # chains if provided to search()
+ #$self->{attrs}{result_class} = $result_class if ref $self;
}
$self->_result_class;
}
return $self->search(@_)->count if @_ and defined $_[0];
return scalar @{ $self->get_cache } if $self->get_cache;
- my @grouped_subq_attrs = qw/prefetch collapse distinct group_by having/;
- my @subq_attrs = ();
-
- my $attrs = $self->_resolved_attrs;
- # if we are not paged - we are simply asking for a limit
- if (not $attrs->{page} and not $attrs->{software_limit}) {
- push @subq_attrs, qw/rows offset/;
+ my $attrs = $self->_resolved_attrs_copy;
+
+ # this is a little optimization - it is faster to do the limit
+ # adjustments in software, instead of a subquery
+ my $rows = delete $attrs->{rows};
+ my $offset = delete $attrs->{offset};
+
+ my $crs;
+ if ($self->_has_resolved_attr (qw/collapse group_by/)) {
+ $crs = $self->_count_subq_rs ($attrs);
+ }
+ else {
+ $crs = $self->_count_rs ($attrs);
}
+ my $count = $crs->next;
- my $need_subq = $self->_has_attr (@subq_attrs);
- my $need_group_subq = $self->_has_attr (@grouped_subq_attrs);
+ $count -= $offset if $offset;
+ $count = $rows if $rows and $rows < $count;
+ $count = 0 if ($count < 0);
- return ($need_subq || $need_group_subq)
- ? $self->_count_subq ($need_group_subq)
- : $self->_count_simple
+ return $count;
}
-sub _count_subq {
- my ($self, $add_group_by) = @_;
+=head2 count_rs
- my $attrs = $self->_resolved_attrs_copy;
+=over 4
- # copy for the subquery, we need to do some adjustments to it too
- my $sub_attrs = { %$attrs };
+=item Arguments: $cond, \%attrs??
- # these can not go in the subquery, and there is no point of ordering it
- delete $sub_attrs->{$_} for qw/prefetch collapse select +select as +as columns +columns order_by/;
+=item Return Value: $count_rs
- # if needed force a group_by and the same set of columns (most databases require this)
- if ($add_group_by) {
+=back
- # if we prefetch, we group_by primary keys only as this is what we would get out of the rs via ->next/->all
- # simply deleting group_by suffices, as the code below will re-fill it
- # Note: we check $attrs, as $sub_attrs has collapse deleted
- if (ref $attrs->{collapse} and keys %{$attrs->{collapse}} ) {
- delete $sub_attrs->{group_by};
- }
+Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
+This can be very handy for subqueries:
- $sub_attrs->{columns} = $sub_attrs->{group_by} ||= [ map { "$attrs->{alias}.$_" } ($self->result_source->primary_columns) ];
- }
+ ->search( { amount => $some_rs->count_rs->as_query } )
- $attrs->{from} = [{
- count_subq => (ref $self)->new ($self->result_source, $sub_attrs )->as_query
- }];
+As with regular resultsets the SQL query will be executed only after
+the resultset is accessed via L</next> or L</all>. That would return
+the same single value obtainable via L</count>.
- # the subquery replaces this
- delete $attrs->{$_} for qw/where bind prefetch collapse distinct group_by having having_bind/;
+=cut
+
+sub count_rs {
+ my $self = shift;
+ return $self->search(@_)->count_rs if @_;
- return $self->__count ($attrs);
+ # this may look like a lack of abstraction (count() does about the same)
+ # but in fact an _rs *must* use a subquery for the limits, as the
+ # software based limiting can not be ported if this $rs is to be used
+ # in a subquery itself (i.e. ->as_query)
+ if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
+ return $self->_count_subq_rs;
+ }
+ else {
+ return $self->_count_rs;
+ }
}
-sub _count_simple {
- my $self = shift;
+#
+# returns a ResultSetColumn object tied to the count query
+#
+sub _count_rs {
+ my ($self, $attrs) = @_;
- my $count = $self->__count;
- return 0 unless $count;
+ my $rsrc = $self->result_source;
+ $attrs ||= $self->_resolved_attrs;
- # need to take offset from resolved attrs
+ my $tmp_attrs = { %$attrs };
+ # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
+ delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
- my $attrs = $self->_resolved_attrs;
+ # overwrite the selector (supplied by the storage)
+ $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
+ $tmp_attrs->{as} = 'count';
- $count -= $attrs->{offset} if $attrs->{offset};
- $count = $attrs->{rows} if $attrs->{rows} and $attrs->{rows} < $count;
- $count = 0 if ($count < 0);
- return $count;
+ my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
+
+ return $tmp_rs;
}
-sub __count {
+#
+# same as above but uses a subquery
+#
+sub _count_subq_rs {
my ($self, $attrs) = @_;
- $attrs ||= $self->_resolved_attrs_copy;
+ my $rsrc = $self->result_source;
+ $attrs ||= $self->_resolved_attrs;
+
+ my $sub_attrs = { %$attrs };
+ # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
+ delete @{$sub_attrs}{qw/collapse select _prefetch_select as order_by for/};
- # take off any column specs, any pagers, record_filter is cdbi, and no point of ordering a count
- delete $attrs->{$_} for (qw/columns +columns select +select as +as rows offset page pager order_by record_filter/);
+ # if we multi-prefetch we group_by primary keys only as this is what we would
+ # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
+ if ( keys %{$attrs->{collapse}} ) {
+ $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } ($rsrc->_pri_cols) ]
+ }
- $attrs->{select} = { count => '*' };
- $attrs->{as} = [qw/count/];
+ # Calculate subquery selector
+ if (my $g = $sub_attrs->{group_by}) {
- my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
- my ($count) = $tmp_rs->cursor->next;
+ my $sql_maker = $rsrc->storage->sql_maker;
- return $count;
+ # necessary as the group_by may refer to aliased functions
+ my $sel_index;
+ for my $sel (@{$attrs->{select}}) {
+ $sel_index->{$sel->{-as}} = $sel
+ if (ref $sel eq 'HASH' and $sel->{-as});
+ }
+
+ for my $g_part (@$g) {
+ my $colpiece = $sel_index->{$g_part} || $g_part;
+
+ # disqualify join-based group_by's. Arcane but possible query
+ # also horrible horrible hack to alias a column (not a func.)
+ # (probably need to introduce SQLA syntax)
+ if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
+ my $as = $colpiece;
+ $as =~ s/\./__/;
+ $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
+ }
+ push @{$sub_attrs->{select}}, $colpiece;
+ }
+ }
+ else {
+ my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
+ $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
+ }
+
+ return $rsrc->resultset_class
+ ->new ($rsrc, $sub_attrs)
+ ->as_subselect_rs
+ ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
+ ->get_column ('count');
}
sub _bool {
my @obj;
- # TODO: don't call resolve here
if (keys %{$self->_resolved_attrs->{collapse}}) {
-# if ($self->{attrs}{prefetch}) {
- # Using $self->cursor->all is really just an optimisation.
- # If we're collapsing has_many prefetches it probably makes
- # very little difference, and this is cleaner than hacking
- # _construct_object to survive the approach
+ # Using $self->cursor->all is really just an optimisation.
+ # If we're collapsing has_many prefetches it probably makes
+ # very little difference, and this is cleaner than hacking
+ # _construct_object to survive the approach
+ $self->cursor->reset;
my @row = $self->cursor->next;
while (@row) {
push(@obj, $self->_construct_object(@row));
}
$self->set_cache(\@obj) if $self->{attrs}{cache};
+
return @obj;
}
=back
Resets the resultset's cursor, so you can iterate through the elements again.
+Implicitly resets the storage cursor, so a subsequent L</next> will trigger
+another query.
=cut
my $rsrc = $self->result_source;
- my $needs_group_by_subq = $self->_has_attr (qw/prefetch distinct join seen_join group_by/);
- my $needs_subq = $self->_has_attr (qw/row offset page/);
+ # if a condition exists we need to strip all table qualifiers
+ # if this is not possible we'll force a subquery below
+ my $cond = $rsrc->schema->storage->_strip_cond_qualifiers ($self->{cond});
+
+ my $needs_group_by_subq = $self->_has_resolved_attr (qw/collapse group_by -join/);
+ my $needs_subq = $needs_group_by_subq || (not defined $cond) || $self->_has_resolved_attr(qw/rows offset/);
if ($needs_group_by_subq or $needs_subq) {
# make a new $rs selecting only the PKs (that's all we really need)
my $attrs = $self->_resolved_attrs_copy;
- delete $attrs->{$_} for qw/prefetch collapse select +select as +as columns +columns/;
- $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->primary_columns) ];
+
+ delete $attrs->{$_} for qw/collapse _collapse_order_by select _prefetch_select as/;
+ $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->_pri_cols) ];
if ($needs_group_by_subq) {
# make sure no group_by was supplied, or if there is one - make sure it matches
if (my $g = $attrs->{group_by}) {
my @current_group_by = map
{ $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
- (ref $g eq 'ARRAY' ? @$g : $g );
+ @$g
+ ;
if (
join ("\x00", sort @current_group_by)
}
my $subrs = (ref $self)->new($rsrc, $attrs);
-
- return $self->result_source->storage->subq_update_delete($subrs, $op, $values);
+ return $self->result_source->storage->_subq_update_delete($subrs, $op, $values);
}
else {
return $rsrc->storage->$op(
$rsrc,
$op eq 'update' ? $values : (),
- $self->_cond_for_update_delete,
+ $cond,
);
}
}
-
-# _cond_for_update_delete
-#
-# update/delete require the condition to be modified to handle
-# the differing SQL syntax available. This transforms the $self->{cond}
-# appropriately, returning the new condition.
-
-sub _cond_for_update_delete {
- my ($self, $full_cond) = @_;
- my $cond = {};
-
- $full_cond ||= $self->{cond};
- # No-op. No condition, we're updating/deleting everything
- return $cond unless ref $full_cond;
-
- if (ref $full_cond eq 'ARRAY') {
- $cond = [
- map {
- my %hash;
- foreach my $key (keys %{$_}) {
- $key =~ /([^.]+)$/;
- $hash{$1} = $_->{$key};
- }
- \%hash;
- } @{$full_cond}
- ];
- }
- elsif (ref $full_cond eq 'HASH') {
- if ((keys %{$full_cond})[0] eq '-and') {
- $cond->{-and} = [];
- my @cond = @{$full_cond->{-and}};
- for (my $i = 0; $i < @cond; $i++) {
- my $entry = $cond[$i];
- my $hash;
- if (ref $entry eq 'HASH') {
- $hash = $self->_cond_for_update_delete($entry);
- }
- else {
- $entry =~ /([^.]+)$/;
- $hash->{$1} = $cond[++$i];
- }
- push @{$cond->{-and}}, $hash;
- }
- }
- else {
- foreach my $key (keys %{$full_cond}) {
- $key =~ /([^.]+)$/;
- $cond->{$1} = $full_cond->{$key};
- }
- }
- }
- else {
- $self->throw_exception("Can't update/delete on resultset with condition unless hash or array");
- }
-
- return $cond;
-}
-
-
=head2 update
=over 4
my ($self, $values) = @_;
$self->throw_exception('Values for update_all must be a hash')
unless ref $values eq 'HASH';
- foreach my $obj ($self->all) {
- $obj->set_columns($values)->update;
- }
+
+ my $guard = $self->result_source->schema->txn_scope_guard;
+ $_->update($values) for $self->all;
+ $guard->commit;
return 1;
}
=item Arguments: none
-=item Return Value: 1
+=item Return Value: $storage_rv
=back
will not run DBIC cascade triggers. See L</delete_all> if you need triggers
to run. See also L<DBIx::Class::Row/delete>.
-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:-
-
-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.
+Return value will be the number of rows deleted; exact type of return value
+is storage-dependent.
=cut
$self->throw_exception('delete_all does not accept any arguments')
if @_;
+ my $guard = $self->result_source->schema->txn_scope_guard;
$_->delete for $self->all;
+ $guard->commit;
return 1;
}
to insert the data, as this is a faster method.
Otherwise, each set of data is inserted into the database using
-L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
-objects is returned.
+L<DBIx::Class::ResultSet/create>, and the resulting objects are
+accumulated into an array. The array itself, or an array reference
+is returned depending on scalar or list context.
Example: Assuming an Artist Class that has many CDs Classes relating:
],
},
{ artistid => 5, name => 'Angsty-Whiny Girl', cds => [
- { title => 'My parents sold me to a record company' ,year => 2005 },
+ { title => 'My parents sold me to a record company', year => 2005 },
{ title => 'Why Am I So Ugly?', year => 2006 },
{ title => 'I Got Surgery and am now Popular', year => 2007 }
],
[qw/artistid name/],
[100, 'A Formally Unknown Singer'],
[101, 'A singer that jumped the shark two albums ago'],
- [102, 'An actually cool singer.'],
+ [102, 'An actually cool singer'],
]);
Please note an important effect on your data when choosing between void and
=cut
sub populate {
- my $self = shift @_;
- my $data = ref $_[0][0] eq 'HASH'
- ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
- $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
+ my $self = shift;
+
+ # cruft placed in standalone method
+ my $data = $self->_normalize_populate_args(@_);
if(defined wantarray) {
my @created;
foreach my $item (@$data) {
push(@created, $self->create($item));
}
- return @created;
+ return wantarray ? @created : \@created;
} else {
- my ($first, @rest) = @$data;
+ my $first = $data->[0];
+
+ # if a column is a registered relationship, and is a non-blessed hash/array, consider
+ # it relationship data
+ my (@rels, @columns);
+ for (keys %$first) {
+ my $ref = ref $first->{$_};
+ $self->result_source->has_relationship($_) && ($ref eq 'ARRAY' or $ref eq 'HASH')
+ ? push @rels, $_
+ : push @columns, $_
+ ;
+ }
- my @names = grep {!ref $first->{$_}} keys %$first;
- my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
my @pks = $self->result_source->primary_columns;
## do the belongs_to relationships
foreach my $index (0..$#$data) {
- if( grep { !defined $data->[$index]->{$_} } @pks ) {
- my @ret = $self->populate($data);
- return;
+
+ # delegate to create() for any dataset without primary keys with specified relationships
+ if (grep { !defined $data->[$index]->{$_} } @pks ) {
+ for my $r (@rels) {
+ if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
+ my @ret = $self->populate($data);
+ return;
+ }
+ }
}
foreach my $rel (@rels) {
- next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
+ next unless ref $data->[$index]->{$rel} eq "HASH";
my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
my $related = $result->result_source->_resolve_condition(
delete $data->[$index]->{$rel};
$data->[$index] = {%{$data->[$index]}, %$related};
- push @names, keys %$related if $index == 0;
+ push @columns, keys %$related if $index == 0;
}
}
- ## do bulk insert on current row
- my @values = map { [ @$_{@names} ] } @$data;
+ ## inherit the data locked in the conditions of the resultset
+ my ($rs_data) = $self->_merge_cond_with_data({});
+ delete @{$rs_data}{@columns};
+ my @inherit_cols = keys %$rs_data;
+ my @inherit_data = values %$rs_data;
+ ## do bulk insert on current row
$self->result_source->storage->insert_bulk(
$self->result_source,
- \@names,
- \@values,
+ [@columns, @inherit_cols],
+ [ map { [ @$_{@columns}, @inherit_data ] } @$data ],
);
## do the has_many relationships
foreach my $rel (@rels) {
next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
- my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
+ my $parent = $self->find({map { $_ => $item->{$_} } @pks})
|| $self->throw_exception('Cannot find the relating object.');
my $child = $parent->$rel;
}
}
-=head2 _normalize_populate_args ($args)
-
-Private method used by L</populate> to normalize its incoming arguments. Factored
-out in case you want to subclass and accept new argument structures to the
-L</populate> method.
-
-=cut
+# populate() argumnets went over several incarnations
+# What we ultimately support is AoH
sub _normalize_populate_args {
- my ($self, $data) = @_;
- my @names = @{shift(@$data)};
- my @results_to_create;
- foreach my $datum (@$data) {
- my %result_to_create;
- foreach my $index (0..$#names) {
- $result_to_create{$names[$index]} = $$datum[$index];
+ my ($self, $arg) = @_;
+
+ if (ref $arg eq 'ARRAY') {
+ if (ref $arg->[0] eq 'HASH') {
+ return $arg;
+ }
+ elsif (ref $arg->[0] eq 'ARRAY') {
+ my @ret;
+ my @colnames = @{$arg->[0]};
+ foreach my $values (@{$arg}[1 .. $#$arg]) {
+ push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
+ }
+ return \@ret;
}
- push @results_to_create, \%result_to_create;
}
- return \@results_to_create;
+
+ $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
}
=head2 pager
=cut
+# make a wizard good for both a scalar and a hashref
+my $mk_lazy_count_wizard = sub {
+ require Variable::Magic;
+
+ my $stash = { total_rs => shift };
+ my $slot = shift; # only used by the hashref magic
+
+ my $magic = Variable::Magic::wizard (
+ data => sub { $stash },
+
+ (!$slot)
+ ? (
+ # the scalar magic
+ get => sub {
+ # set value lazily, and dispell for good
+ ${$_[0]} = $_[1]{total_rs}->count;
+ Variable::Magic::dispell (${$_[0]}, $_[1]{magic_selfref});
+ return 1;
+ },
+ set => sub {
+ # an explicit set implies dispell as well
+ # the unless() is to work around "fun and giggles" below
+ Variable::Magic::dispell (${$_[0]}, $_[1]{magic_selfref})
+ unless (caller(2))[3] eq 'DBIx::Class::ResultSet::pager';
+ return 1;
+ },
+ )
+ : (
+ # the uvar magic
+ fetch => sub {
+ if ($_[2] eq $slot and !$_[1]{inactive}) {
+ my $cnt = $_[1]{total_rs}->count;
+ $_[0]->{$slot} = $cnt;
+
+ # attempting to dispell in a fetch handle (works in store), seems
+ # to invariable segfault on 5.10, 5.12, 5.13 :(
+ # so use an inactivator instead
+ #Variable::Magic::dispell (%{$_[0]}, $_[1]{magic_selfref});
+ $_[1]{inactive}++;
+ }
+ return 1;
+ },
+ store => sub {
+ if (! $_[1]{inactive} and $_[2] eq $slot) {
+ #Variable::Magic::dispell (%{$_[0]}, $_[1]{magic_selfref});
+ $_[1]{inactive}++
+ unless (caller(2))[3] eq 'DBIx::Class::ResultSet::pager';
+ }
+ return 1;
+ },
+ ),
+ );
+
+ $stash->{magic_selfref} = $magic;
+ weaken ($stash->{magic_selfref}); # this fails on 5.8.1
+
+ return $magic;
+};
+
+# the tie class for 5.8.1
+{
+ package DBIx::Class::__DBIC_LAZY_RS_COUNT__;
+ use base qw/Tie::Hash/;
+
+ sub FIRSTKEY { my $dummy = scalar keys %{$_[0]{data}}; each %{$_[0]{data}} }
+ sub NEXTKEY { each %{$_[0]{data}} }
+ sub EXISTS { exists $_[0]{data}{$_[1]} }
+ sub DELETE { delete $_[0]{data}{$_[1]} }
+ sub CLEAR { %{$_[0]{data}} = () }
+ sub SCALAR { scalar %{$_[0]{data}} }
+
+ sub TIEHASH {
+ $_[1]{data} = {%{$_[1]{selfref}}};
+ %{$_[1]{selfref}} = ();
+ Scalar::Util::weaken ($_[1]{selfref});
+ return bless ($_[1], $_[0]);
+ };
+
+ sub FETCH {
+ if ($_[1] eq $_[0]{slot}) {
+ my $cnt = $_[0]{data}{$_[1]} = $_[0]{total_rs}->count;
+ untie %{$_[0]{selfref}};
+ %{$_[0]{selfref}} = %{$_[0]{data}};
+ return $cnt;
+ }
+ else {
+ $_[0]{data}{$_[1]};
+ }
+ }
+
+ sub STORE {
+ $_[0]{data}{$_[1]} = $_[2];
+ if ($_[1] eq $_[0]{slot}) {
+ untie %{$_[0]{selfref}};
+ %{$_[0]{selfref}} = %{$_[0]{data}};
+ }
+ $_[2];
+ }
+}
+
sub pager {
my ($self) = @_;
return $self->{pager} if $self->{pager};
+ if ($self->get_cache) {
+ $self->throw_exception ('Pagers on cached resultsets are not supported');
+ }
+
my $attrs = $self->{attrs};
$self->throw_exception("Can't create pager for non-paged rs")
unless $self->{attrs}{page};
# with a subselect) to get the real total count
my $count_attrs = { %$attrs };
delete $count_attrs->{$_} for qw/rows offset page pager/;
- my $total_count = (ref $self)->new($self->result_source, $count_attrs)->count;
+ my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
+
- return $self->{pager} = Data::Page->new(
- $total_count,
+### the following may seem awkward and dirty, but it's a thought-experiment
+### necessary for future development of DBIx::DS. Do *NOT* change this code
+### before talking to ribasushi/mst
+
+ my $pager = Data::Page->new(
+ 0, #start with an empty set
$attrs->{rows},
- $self->{attrs}{page}
+ $self->{attrs}{page},
);
+
+ my $data_slot = 'total_entries';
+
+ # Since we are interested in a cached value (once it's set - it's set), every
+ # technique will detach from the magic-host once the time comes to fire the
+ # ->count (or in the segfaulting case of >= 5.10 it will deactivate itself)
+
+ if ($] < 5.008003) {
+ # 5.8.1 throws 'Modification of a read-only value attempted' when one tries
+ # to weakref the magic container :(
+ # tested on 5.8.1
+ tie (%$pager, 'DBIx::Class::__DBIC_LAZY_RS_COUNT__',
+ { slot => $data_slot, total_rs => $total_rs, selfref => $pager }
+ );
+ }
+ elsif ($] < 5.010) {
+ # We can use magic on the hash value slot. It's interesting that the magic is
+ # attached to the hash-slot, and does *not* stop working once I do the dummy
+ # assignments after the cast()
+ # tested on 5.8.3 and 5.8.9
+ my $magic = $mk_lazy_count_wizard->($total_rs);
+ Variable::Magic::cast ( $pager->{$data_slot}, $magic );
+
+ # this is for fun and giggles
+ $pager->{$data_slot} = -1;
+ $pager->{$data_slot} = 0;
+
+ # this does not work for scalars, but works with
+ # uvar magic below
+ #my %vals = %$pager;
+ #%$pager = ();
+ #%{$pager} = %vals;
+ }
+ else {
+ # And the uvar magic
+ # works on 5.10.1, 5.12.1 and 5.13.4 in its current form,
+ # however see the wizard maker for more notes
+ my $magic = $mk_lazy_count_wizard->($total_rs, $data_slot);
+ Variable::Magic::cast ( %$pager, $magic );
+
+ # still works
+ $pager->{$data_slot} = -1;
+ $pager->{$data_slot} = 0;
+
+ # this now works
+ my %vals = %$pager;
+ %$pager = ();
+ %{$pager} = %vals;
+ }
+
+ return $self->{pager} = $pager;
}
=head2 page
$self->throw_exception( "new_result needs a hash" )
unless (ref $values eq 'HASH');
- my %new;
+ my ($merged_cond, $cols_from_relations) = $self->_merge_cond_with_data($values);
+
+ my %new = (
+ %$merged_cond,
+ @$cols_from_relations
+ ? (-cols_from_relations => $cols_from_relations)
+ : (),
+ -source_handle => $self->_source_handle,
+ -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
+ );
+
+ return $self->result_class->new(\%new);
+}
+
+# _merge_cond_with_data
+#
+# Takes a simple hash of K/V data and returns its copy merged with the
+# condition already present on the resultset. Additionally returns an
+# arrayref of value/condition names, which were inferred from related
+# objects (this is needed for in-memory related objects)
+sub _merge_cond_with_data {
+ my ($self, $data) = @_;
+
+ my (%new_data, @cols_from_relations);
+
my $alias = $self->{attrs}{alias};
- if (
- defined $self->{cond}
- && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
- ) {
- %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
- $new{-from_resultset} = [ keys %new ] if keys %new;
- } else {
+ if (! defined $self->{cond}) {
+ # just massage $data below
+ }
+ elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
+ %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
+ @cols_from_relations = keys %new_data;
+ }
+ elsif (ref $self->{cond} ne 'HASH') {
$self->throw_exception(
- "Can't abstract implicit construct, condition not a hash"
- ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
-
- my $collapsed_cond = (
- $self->{cond}
- ? $self->_collapse_cond($self->{cond})
- : {}
+ "Can't abstract implicit construct, resultset condition not a hash"
);
-
+ }
+ else {
# 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->{'='};
+ my $collapsed_cond = $self->_collapse_cond($self->{cond});
+ 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 '=') {
+ $new_data{$col} = $value->{'='};
next;
}
- $new{$col} = $value if $self->_is_deterministic_value($value);
+ $new_data{$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
+ %new_data = (
+ %new_data,
+ %{ $self->_remove_alias($data, $alias) },
);
- return $self->result_class->new(\%new);
+ return (\%new_data, \@cols_from_relations);
}
# _is_deterministic_value
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 1 if blessed $value;
return 0;
}
-# _has_attr
+# _has_resolved_attr
#
# determines if the resultset defines at least one
# of the attributes supplied
#
# used to determine if a subquery is neccessary
+#
+# supports some virtual attributes:
+# -join
+# This will scan for any joins being present on the resultset.
+# It is not a mere key-search but a deep inspection of {from}
+#
-sub _has_attr {
+sub _has_resolved_attr {
my ($self, @attr_names) = @_;
my $attrs = $self->_resolved_attrs;
- my $join_check_req;
+ my %extra_checks;
for my $n (@attr_names) {
- ++$join_check_req if $n =~ /join/;
+ if (grep { $n eq $_ } (qw/-join/) ) {
+ $extra_checks{$n}++;
+ next;
+ }
my $attr = $attrs->{$n};
}
}
- # a join can be expressed as a multi-level from
+ # a resolved join is expressed as a multi-level from
return 1 if (
- $join_check_req
+ $extra_checks{-join}
and
ref $attrs->{from} eq 'ARRAY'
and
return \%unaliased;
}
-=head2 as_query (EXPERIMENTAL)
+=head2 as_query
=over 4
This is generally used as the RHS for a subquery.
-B<NOTE>: This feature is still experimental.
-
=cut
-sub as_query { return shift->cursor->as_query(@_) }
+sub as_query {
+ my $self = shift;
+
+ my $attrs = $self->_resolved_attrs_copy;
+
+ # For future use:
+ #
+ # in list ctx:
+ # my ($sql, \@bind, \%dbi_bind_attrs) = _select_args_to_query (...)
+ # $sql also has no wrapping parenthesis in list ctx
+ #
+ my $sqlbind = $self->result_source->storage
+ ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
+
+ return $sqlbind;
+}
=head2 find_or_new
a unique constraint that is not the primary key, or looking for
related rows.
-If you want objects to be saved immediately, use L</find_or_create> instead.
+If you want objects to be saved immediately, use L</find_or_create>
+instead.
-B<Note>: C<find_or_new> 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<undef>
-will cause L</find> to attempt to search for a row with a value of
-I<NULL>.
+B<Note>: Take care when using C<find_or_new> with a table having
+columns with default values that you intend to be automatically
+supplied by the database (e.g. an auto_increment primary key column).
+In normal usage, the value of such columns should NOT be included at
+all in the call to C<find_or_new>, even when set to C<undef>.
=cut
my $self = shift;
my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
- my $exists = $self->find($hash, $attrs);
- return defined $exists ? $exists : $self->new_result($hash);
+ if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
+ return $row;
+ }
+ return $self->new_result($hash);
}
=head2 create
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
+transparently 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
);
Example of creating a new row and also creating a row in a related
-C<belongs_to>resultset. Note Hashref.
+C<belongs_to> resultset. Note Hashref.
$cd_rs->create({
title=>"Music for Silly Walks",
}
});
+=over
+
+=item WARNING
+
+When subclassing ResultSet never attempt to override this method. Since
+it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
+lot of the internals simply never call it, so your override will be
+bypassed more often than not. Override either L<new|DBIx::Class::Row/new>
+or L<insert|DBIx::Class::Row/insert> depending on how early in the
+L</create> process you need to intervene.
+
+=back
+
=cut
sub create {
=back
$cd->cd_to_producer->find_or_create({ producer => $producer },
- { key => 'primary });
+ { key => 'primary' });
Tries to find a record based on its primary key or unique constraints; if none
is found, creates one and returns that instead.
the find has completed and before the create has started. To avoid
this problem, use find_or_create() inside a transaction.
-B<Note>: C<find_or_create> 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<undef>
-will cause L</find> to attempt to search for a row with a value of
-I<NULL>.
+B<Note>: Take care when using C<find_or_create> with a table having
+columns with default values that you intend to be automatically
+supplied by the database (e.g. an auto_increment primary key column).
+In normal usage, the value of such columns should NOT be included at
+all in the call to C<find_or_create>, even when set to C<undef>.
See also L</find> and L</update_or_create>. For information on how to declare
unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
my $self = shift;
my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
- my $exists = $self->find($hash, $attrs);
- return defined $exists ? $exists : $self->create($hash);
+ if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
+ return $row;
+ }
+ return $self->create($hash);
}
=head2 update_or_create
producer => $producer,
name => 'harry',
}, {
- key => 'primary,
+ key => 'primary',
});
See also L</find> and L</find_or_create>. For information on how to declare
unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
-B<Note>: C<update_or_create> 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<undef> will cause L</find> to attempt to
-search for a row with a value of I<NULL>.
+B<Note>: Take care when using C<update_or_create> with a table having
+columns with default values that you intend to be automatically
+supplied by the database (e.g. an auto_increment primary key column).
+In normal usage, the value of such columns should NOT be included at
+all in the call to C<update_or_create>, even when set to C<undef>.
=cut
$cd->insert;
}
-See also L</find>, L</find_or_create> and L<find_or_new>.
+B<Note>: Take care when using C<update_or_new> with a table having
+columns with default values that you intend to be automatically
+supplied by the database (e.g. an auto_increment primary key column).
+In normal usage, the value of such columns should NOT be included at
+all in the call to C<update_or_new>, even when set to C<undef>.
+
+See also L</find>, L</find_or_create> and L</find_or_new>.
=cut
shift->set_cache(undef);
}
+=head2 is_paged
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: true, if the resultset has been paginated
+
+=back
+
+=cut
+
+sub is_paged {
+ my ($self) = @_;
+ return !!$self->{attrs}{page};
+}
+
+=head2 is_ordered
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: true, if the resultset has been ordered with C<order_by>.
+
+=back
+
+=cut
+
+sub is_ordered {
+ my ($self) = @_;
+ return scalar $self->result_source->storage->_parse_order_by($self->{attrs}{order_by});
+}
+
=head2 related_resultset
=over 4
$self->{related_resultsets} ||= {};
return $self->{related_resultsets}{$rel} ||= do {
- my $rel_obj = $self->result_source->relationship_info($rel);
+ my $rsrc = $self->result_source;
+ my $rel_info = $rsrc->relationship_info($rel);
$self->throw_exception(
- "search_related: result source '" . $self->result_source->source_name .
+ "search_related: result source '" . $rsrc->source_name .
"' has no such relationship $rel")
- unless $rel_obj;
+ unless $rel_info;
+
+ my $attrs = $self->_chain_relationship($rel);
- my ($from,$seen) = $self->_resolve_from($rel);
+ my $join_count = $attrs->{seen_join}{$rel};
+
+ my $alias = $self->result_source->storage
+ ->relname_to_table_alias($rel, $join_count);
+
+ # since this is search_related, and we already slid the select window inwards
+ # (the select/as attrs were deleted in the beginning), we need to flip all
+ # left joins to inner, so we get the expected results
+ # read the comment on top of the actual function to see what this does
+ $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
- my $join_count = $seen->{$rel};
- my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
#XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
- my %attrs = %{$self->{attrs}||{}};
- delete @attrs{qw(result_class alias)};
+ delete @{$attrs}{qw(result_class alias)};
my $new_cache;
}
}
- my $rel_source = $self->result_source->related_source($rel);
+ my $rel_source = $rsrc->related_source($rel);
my $new = do {
# to work sanely (e.g. RestrictWithObject wants to be able to add
# extra query restrictions, and these may need to be $alias.)
- my $attrs = $rel_source->resultset_attributes;
- local $attrs->{alias} = $alias;
+ my $rel_attrs = $rel_source->resultset_attributes;
+ local $rel_attrs->{alias} = $alias;
$rel_source->resultset
->search_rs(
undef, {
- %attrs,
- join => undef,
- prefetch => undef,
- select => undef,
- as => undef,
- where => $self->{cond},
- seen_join => $seen,
- from => $from,
+ %$attrs,
+ where => $attrs->{where},
});
};
$new->set_cache($new_cache) if $new_cache;
return ($self->{attrs} || {})->{alias} || 'me';
}
+=head2 as_subselect_rs
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $resultset
+
+=back
+
+Act as a barrier to SQL symbols. The resultset provided will be made into a
+"virtual view" by including it as a subquery within the from clause. From this
+point on, any joined tables are inaccessible to ->search on the resultset (as if
+it were simply where-filtered without joins). For example:
+
+ my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
+
+ # 'x' now pollutes the query namespace
+
+ # So the following works as expected
+ my $ok_rs = $rs->search({'x.other' => 1});
+
+ # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
+ # def) we look for one row with contradictory terms and join in another table
+ # (aliased 'x_2') which we never use
+ my $broken_rs = $rs->search({'x.name' => 'def'});
+
+ my $rs2 = $rs->as_subselect_rs;
+
+ # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
+ my $not_joined_rs = $rs2->search({'x.other' => 1});
+
+ # works as expected: finds a 'table' row related to two x rows (abc and def)
+ my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
+
+Another example of when one might use this would be to select a subset of
+columns in a group by clause:
+
+ my $rs = $schema->resultset('Bar')->search(undef, {
+ group_by => [qw{ id foo_id baz_id }],
+ })->as_subselect_rs->search(undef, {
+ columns => [qw{ id foo_id }]
+ });
+
+In the above example normally columns would have to be equal to the group by,
+but because we isolated the group by into a subselect the above works.
+
+=cut
+
+sub as_subselect_rs {
+ my $self = shift;
+
+ my $attrs = $self->_resolved_attrs;
+
+ my $fresh_rs = (ref $self)->new (
+ $self->result_source
+ );
+
+ # these pieces will be locked in the subquery
+ delete $fresh_rs->{cond};
+ delete @{$fresh_rs->{attrs}}{qw/where bind/};
+
+ return $fresh_rs->search( {}, {
+ from => [{
+ $attrs->{alias} => $self->as_query,
+ -alias => $attrs->{alias},
+ -source_handle => $self->result_source->handle,
+ }],
+ alias => $attrs->{alias},
+ });
+}
+
# This code is called by search_related, and makes sure there
# is clear separation between the joins before, during, and
# after the relationship. This information is needed later
# in order to properly resolve prefetch aliases (any alias
# with a relation_chain_depth less than the depth of the
# current prefetch is not considered)
-sub _resolve_from {
- my ($self, $extra_join) = @_;
+#
+# The increments happen twice per join. An even number means a
+# relationship specified via a search_related, whereas an odd
+# number indicates a join/prefetch added via attributes
+#
+# Also this code will wrap the current resultset (the one we
+# chain to) in a subselect IFF it contains limiting attributes
+sub _chain_relationship {
+ my ($self, $rel) = @_;
my $source = $self->result_source;
- my $attrs = $self->{attrs};
-
- my $from = $attrs->{from}
- || [ { $attrs->{alias} => $source->from } ];
-
- my $seen = { %{$attrs->{seen_join}||{}} };
+ my $attrs = { %{$self->{attrs}||{}} };
# we need to take the prefetch the attrs into account before we
# ->_resolve_join as otherwise they get lost - captainL
- my $merged = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
+ my $join = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
- push @$from, $source->_resolve_join($merged, $attrs->{alias}, $seen) if ($merged);
+ delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
- ++$seen->{-relation_chain_depth};
+ my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
- push @$from, $source->_resolve_join($extra_join, $attrs->{alias}, $seen);
+ my $from;
+ my @force_subq_attrs = qw/offset rows group_by having/;
- ++$seen->{-relation_chain_depth};
+ if (
+ ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
+ ||
+ $self->_has_resolved_attr (@force_subq_attrs)
+ ) {
+ # Nuke the prefetch (if any) before the new $rs attrs
+ # are resolved (prefetch is useless - we are wrapping
+ # a subquery anyway).
+ my $rs_copy = $self->search;
+ $rs_copy->{attrs}{join} = $self->_merge_attr (
+ $rs_copy->{attrs}{join},
+ delete $rs_copy->{attrs}{prefetch},
+ );
+
+ $from = [{
+ -source_handle => $source->handle,
+ -alias => $attrs->{alias},
+ $attrs->{alias} => $rs_copy->as_query,
+ }];
+ delete @{$attrs}{@force_subq_attrs, qw/where bind/};
+ $seen->{-relation_chain_depth} = 0;
+ }
+ elsif ($attrs->{from}) { #shallow copy suffices
+ $from = [ @{$attrs->{from}} ];
+ }
+ else {
+ $from = [{
+ -source_handle => $source->handle,
+ -alias => $attrs->{alias},
+ $attrs->{alias} => $source->from,
+ }];
+ }
+
+ my $jpath = ($seen->{-relation_chain_depth})
+ ? $from->[-1][0]{-join_path}
+ : [];
+
+ my @requested_joins = $source->_resolve_join(
+ $join,
+ $attrs->{alias},
+ $seen,
+ $jpath,
+ );
+
+ push @$from, @requested_joins;
+
+ $seen->{-relation_chain_depth}++;
+
+ # if $self already had a join/prefetch specified on it, the requested
+ # $rel might very well be already included. What we do in this case
+ # is effectively a no-op (except that we bump up the chain_depth on
+ # the join in question so we could tell it *is* the search_related)
+ my $already_joined;
+
+ # we consider the last one thus reverse
+ for my $j (reverse @requested_joins) {
+ my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
+ if ($rel eq $last_j) {
+ $j->[0]{-relation_chain_depth}++;
+ $already_joined++;
+ last;
+ }
+ }
+
+ unless ($already_joined) {
+ push @$from, $source->_resolve_join(
+ $rel,
+ $attrs->{alias},
+ $seen,
+ $jpath,
+ );
+ }
- return ($from,$seen);
+ $seen->{-relation_chain_depth}++;
+
+ return {%$attrs, from => $from, seen_join => $seen};
}
# too many times we have to do $attrs = { %{$self->_resolved_attrs} }
# build columns (as long as select isn't set) into a set of as/select hashes
unless ( $attrs->{select} ) {
- @colbits = map {
- ( ref($_) eq 'HASH' )
- ? $_
- : {
- (
- /^\Q${alias}.\E(.+)$/
- ? "$1"
- : "$_"
- )
- =>
- (
- /\./
- ? "$_"
- : "${alias}.$_"
- )
- }
- } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
+
+ my @cols;
+ if ( ref $attrs->{columns} eq 'ARRAY' ) {
+ @cols = @{ delete $attrs->{columns}}
+ } elsif ( defined $attrs->{columns} ) {
+ @cols = delete $attrs->{columns}
+ } else {
+ @cols = $source->columns
+ }
+
+ for (@cols) {
+ if ( ref $_ eq 'HASH' ) {
+ push @colbits, $_
+ } else {
+ my $key = /^\Q${alias}.\E(.+)$/
+ ? "$1"
+ : "$_";
+ my $value = /\./
+ ? "$_"
+ : "${alias}.$_";
+ push @colbits, { $key => $value };
+ }
+ }
}
+
# add the additional columns on
- foreach ( 'include_columns', '+columns' ) {
- push @colbits, map {
- ( ref($_) eq 'HASH' )
- ? $_
- : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
- } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
+ foreach (qw{include_columns +columns}) {
+ if ( $attrs->{$_} ) {
+ my @list = ( ref($attrs->{$_}) eq 'ARRAY' )
+ ? @{ delete $attrs->{$_} }
+ : delete $attrs->{$_};
+ for (@list) {
+ if ( ref($_) eq 'HASH' ) {
+ push @colbits, $_
+ } else {
+ my $key = ( split /\./, $_ )[-1];
+ my $value = ( /\./ ? $_ : "$alias.$_" );
+ push @colbits, { $key => $value };
+ }
+ }
+ }
}
# start with initial select items
( ref $attrs->{select} eq 'ARRAY' )
? [ @{ $attrs->{select} } ]
: [ $attrs->{select} ];
- $attrs->{as} = (
- $attrs->{as}
- ? (
- ref $attrs->{as} eq 'ARRAY'
- ? [ @{ $attrs->{as} } ]
- : [ $attrs->{as} ]
+
+ if ( $attrs->{as} ) {
+ $attrs->{as} =
+ (
+ ref $attrs->{as} eq 'ARRAY'
+ ? [ @{ $attrs->{as} } ]
+ : [ $attrs->{as} ]
)
- : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
- );
+ } else {
+ $attrs->{as} = [ map {
+ m/^\Q${alias}.\E(.+)$/
+ ? $1
+ : $_
+ } @{ $attrs->{select} }
+ ]
+ }
}
else {
}
# now add colbits to select/as
- push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
- push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
+ push @{ $attrs->{select} }, map values %{$_}, @colbits;
+ push @{ $attrs->{as} }, map keys %{$_}, @colbits;
- my $adds;
- if ( $adds = delete $attrs->{'+select'} ) {
+ if ( my $adds = delete $attrs->{'+select'} ) {
$adds = [$adds] unless ref $adds eq 'ARRAY';
- push(
- @{ $attrs->{select} },
- map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
- );
+ push @{ $attrs->{select} },
+ map { /\./ || ref $_ ? $_ : "$alias.$_" } @$adds;
}
- if ( $adds = delete $attrs->{'+as'} ) {
+ if ( my $adds = delete $attrs->{'+as'} ) {
$adds = [$adds] unless ref $adds eq 'ARRAY';
- push( @{ $attrs->{as} }, @$adds );
+ push @{ $attrs->{as} }, @$adds;
}
- $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
+ $attrs->{from} ||= [{
+ -source_handle => $source->handle,
+ -alias => $self->{attrs}{alias},
+ $self->{attrs}{alias} => $source->from,
+ }];
+
+ if ( $attrs->{join} || $attrs->{prefetch} ) {
+
+ $self->throw_exception ('join/prefetch can not be used with a custom {from}')
+ if ref $attrs->{from} ne 'ARRAY';
- if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
my $join = delete $attrs->{join} || {};
if ( defined $attrs->{prefetch} ) {
$join = $self->_merge_attr( $join, $attrs->{prefetch} );
-
}
$attrs->{from} = # have to copy here to avoid corrupting the original
[
- @{ $attrs->{from} },
- $source->_resolve_join(
- $join, $alias, { %{ $attrs->{seen_join} || {} } }
- )
+ @{ $attrs->{from} },
+ $source->_resolve_join(
+ $join,
+ $alias,
+ { %{ $attrs->{seen_join} || {} } },
+ ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
+ ? $attrs->{from}[-1][0]{-join_path}
+ : []
+ ,
+ )
];
-
}
- if ( $attrs->{order_by} ) {
+ if ( defined $attrs->{order_by} ) {
$attrs->{order_by} = (
ref( $attrs->{order_by} ) eq 'ARRAY'
? [ @{ $attrs->{order_by} } ]
- : [ $attrs->{order_by} ]
+ : [ $attrs->{order_by} || () ]
);
}
- else {
- $attrs->{order_by} = [];
- }
- my $collapse = $attrs->{collapse} || {};
- if ( my $prefetch = delete $attrs->{prefetch} ) {
- $prefetch = $self->_merge_attr( {}, $prefetch );
- my @pre_order;
- foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
-
- # bring joins back to level of current class
- my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
- my @prefetch =
- $source->_resolve_prefetch( $p, $alias, $join_map, \@pre_order, $collapse );
- push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
- push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
- }
- push( @{ $attrs->{order_by} }, @pre_order );
+ if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
+ $attrs->{group_by} = [ $attrs->{group_by} ];
}
+ # generate the distinct induced group_by early, as prefetch will be carried via a
+ # subquery (since a group_by is present)
if (delete $attrs->{distinct}) {
- $attrs->{group_by} ||= [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ];
- }
+ if ($attrs->{group_by}) {
+ carp ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
+ }
+ else {
+ my $storage = $self->result_source->schema->storage;
+ my $rs_column_list = $storage->_resolve_column_info ($attrs->{from});
+
+ my $group_spec = $attrs->{group_by} = [];
+ my %group_index;
+
+ for (@{$attrs->{select}}) {
+ if (! ref($_) or ref ($_) ne 'HASH' ) {
+ push @$group_spec, $_;
+ $group_index{$_}++;
+ if ($rs_column_list->{$_} and $_ !~ /\./ ) {
+ # add a fully qualified version as well
+ $group_index{"$rs_column_list->{$_}{-source_alias}.$_"}++;
+ }
+ }
+ }
+ # add any order_by parts that are not already present in the group_by
+ # we need to be careful not to add any named functions/aggregates
+ # i.e. select => [ ... { count => 'foo', -as 'foocount' } ... ]
+ for my $chunk ($storage->_parse_order_by($attrs->{order_by})) {
- $attrs->{collapse} = $collapse;
+ # only consider real columns (for functions the user got to do an explicit group_by)
+ my $colinfo = $rs_column_list->{$chunk}
+ or next;
- if ( $attrs->{page} and not defined $attrs->{offset} ) {
- $attrs->{offset} = ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
+ $chunk = "$colinfo->{-source_alias}.$chunk" if $chunk !~ /\./;
+ push @$group_spec, $chunk unless $group_index{$chunk}++;
+ }
+ }
}
- return $self->{_attrs} = $attrs;
-}
+ $attrs->{collapse} ||= {};
+ if ( my $prefetch = delete $attrs->{prefetch} ) {
+ $prefetch = $self->_merge_attr( {}, $prefetch );
+
+ my $prefetch_ordering = [];
+
+ # this is a separate structure (we don't look in {from} directly)
+ # as the resolver needs to shift things off the lists to work
+ # properly (identical-prefetches on different branches)
+ my $join_map = {};
+ if (ref $attrs->{from} eq 'ARRAY') {
+
+ my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
+
+ for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
+ next unless $j->[0]{-alias};
+ next unless $j->[0]{-join_path};
+ next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
+
+ my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
+
+ my $p = $join_map;
+ $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
+ push @{$p->{-join_aliases} }, $j->[0]{-alias};
+ }
+ }
-sub _joinpath_aliases {
- my ($self, $fromspec, $seen) = @_;
+ my @prefetch =
+ $source->_resolve_prefetch( $prefetch, $alias, $join_map, $prefetch_ordering, $attrs->{collapse} );
- my $paths = {};
- return $paths unless ref $fromspec eq 'ARRAY';
+ # we need to somehow mark which columns came from prefetch
+ $attrs->{_prefetch_select} = [ map { $_->[0] } @prefetch ];
- for my $j (@$fromspec) {
+ push @{ $attrs->{select} }, @{$attrs->{_prefetch_select}};
+ push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
- next if ref $j ne 'ARRAY';
- next if $j->[0]{-relation_chain_depth} < ( $seen->{-relation_chain_depth} || 0);
+ push( @{$attrs->{order_by}}, @$prefetch_ordering );
+ $attrs->{_collapse_order_by} = \@$prefetch_ordering;
+ }
- my $p = $paths;
- $p = $p->{$_} ||= {} for @{$j->[0]{-join_path}};
- push @{$p->{-join_aliases} }, $j->[0]{-join_alias};
+ # if both page and offset are specified, produce a combined offset
+ # even though it doesn't make much sense, this is what pre 081xx has
+ # been doing
+ if (my $page = delete $attrs->{page}) {
+ $attrs->{offset} =
+ ($attrs->{rows} * ($page - 1))
+ +
+ ($attrs->{offset} || 0)
+ ;
}
- return $paths;
+ return $self->{_attrs} = $attrs;
}
sub _rollout_attr {
sub _calculate_score {
my ($self, $a, $b) = @_;
+ if (defined $a xor defined $b) {
+ return 0;
+ }
+ elsif (not defined $a) {
+ return 1;
+ }
+
if (ref $b eq 'HASH') {
my ($b_key) = keys %{$b};
if (ref $a eq 'HASH') {
sub throw_exception {
my $self=shift;
+
if (ref $self && $self->_source_handle->schema) {
$self->_source_handle->schema->throw_exception(@_)
- } else {
- croak(@_);
}
-
+ else {
+ DBIx::Class::Exception->throw(@_);
+ }
}
# XXX: FIXME: Attributes docs need clearing up
=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:
C<select> as normal. (You may also use the C<cols> attribute, as in
earlier versions of DBIC.)
+Essentially C<columns> does the same as L</select> and L</as>.
+
+ columns => [ 'foo', { bar => 'baz' } ]
+
+is the same as
+
+ select => [qw/foo baz/],
+ as => [qw/foo bar/]
+
=head2 +columns
=over 4
select => [
'name',
{ count => 'employeeid' },
- { sum => 'salary' }
+ { max => { length => 'name' }, -as => 'longest_name' }
]
});
-When you use function/stored procedure names and do not supply an C<as>
-attribute, the column names returned are storage-dependent. E.g. MySQL would
-return a column named C<count(employeeid)> in the above example.
+ # Equivalent SQL
+ SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
+
+B<NOTE:> You will almost always need a corresponding L</as> attribute when you
+use L</select>, to instruct DBIx::Class how to store the result of the column.
+Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
+identifier aliasing. You can however alias a function, so you can use it in
+e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
+attribute> supplied as shown in the example above.
=head2 +select
=over 4
Indicates additional columns to be selected from storage. Works the same as
-L</select> but adds columns to the selection.
+L</select> but adds columns to the default selection, instead of specifying
+an explicit list.
=back
=back
-Indicates column names for object inflation. That is, C<as>
-indicates the name that the column can be accessed as via the
-C<get_column> method (or via the object accessor, B<if one already
-exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
-
-The C<as> attribute is used in conjunction with C<select>,
-usually when C<select> contains one or more function or stored
-procedure names:
+Indicates column names for object inflation. That is L</as> indicates the
+slot name in which the column value will be stored within the
+L<Row|DBIx::Class::Row> object. The value will then be accessible via this
+identifier by the C<get_column> method (or via the object accessor B<if one
+with the same name already exists>) as shown below. The L</as> attribute has
+B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
$rs = $schema->resultset('Employee')->search(undef, {
select => [
'name',
- { count => 'employeeid' }
+ { count => 'employeeid' },
+ { max => { length => 'name' }, -as => 'longest_name' }
],
- as => ['name', 'employee_count'],
+ as => [qw/
+ name
+ employee_count
+ max_name_length
+ /],
});
- my $employee = $rs->first(); # get the first Employee
-
If the object against which the search is performed already has an accessor
matching a column name specified in C<as>, the value can be retrieved using
the accessor as normal:
You can create your own accessors if required - see
L<DBIx::Class::Manual::Cookbook> for details.
-Please note: This will NOT insert an C<AS employee_count> into the SQL
-statement produced, it is used for internal access only. Thus
-attempting to use the accessor in an C<order_by> clause or similar
-will fail miserably.
-
-To get around this limitation, you can supply literal SQL to your
-C<select> attibute that contains the C<AS alias> text, eg:
-
- select => [\'myfield AS alias']
-
=head2 join
=over 4
C<prefetch> can be used with the following relationship types: C<belongs_to>,
C<has_one> (or if you're using C<add_relationship>, any relationship declared
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
+prefetches an artists cds, the tracks on those cds, and the tags associated
with that artist is given below (assuming many-to-many from artists to tags):
my $rs = $schema->resultset('Artist')->search(
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, '==', $prefetch_count, "Counts should be the same" );
+
+that cmp_ok() may or may not pass depending on the datasets involved. This
+behavior may or may not survive the 0.09 transition.
+
+=back
+
=head2 page
=over 4
identical to creating a non-pages resultset and then calling ->page($page)
on it.
-If L<rows> attribute is not specified it defualts to 10 rows per page.
+If L<rows> attribute is not specified it defaults to 10 rows per page.
When you have a paged resultset, L</count> will only return the number
of rows in the page. To get the total, use the L</pager> and call
=back
-Specifes the maximum number of rows for direct retrieval or the number of
+Specifies the maximum number of rows for direct retrieval or the number of
rows per page if the page attribute or method is used.
=head2 offset
=back
-Set to 1 to group by all columns.
+Set to 1 to group by all columns. If the resultset already has a group_by
+attribute, this setting is ignored and an appropriate warning is issued.
=head2 where
# only return rows WHERE deleted IS NULL for all searches
__PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
-Can be overridden by passing C<{ where => undef }> as an attribute
-to a resulset.
+Can be overridden by passing C<< { where => undef } >> as an attribute
+to a resultset.
=back
For more examples of using these attributes, see
L<DBIx::Class::Manual::Cookbook>.
-=head2 from
-
-=over 4
-
-=item Value: \@from_clause
-
-=back
-
-The C<from> attribute gives you manual control over the C<FROM> clause of SQL
-statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
-clauses.
-
-NOTE: Use this on your own risk. This allows you to shoot off your foot!
-
-C<join> will usually do what you need and it is strongly recommended that you
-avoid using C<from> unless you cannot achieve the desired result using C<join>.
-And we really do mean "cannot", not just tried and failed. Attempting to use
-this because you're having problems with C<join> is like trying to use x86
-ASM because you've got a syntax error in your C. Trust us on this.
-
-Now, if you're still really, really sure you need to use this (and if you're
-not 100% sure, ask the mailing list first), here's an explanation of how this
-works.
-
-The syntax is as follows -
-
- [
- { <alias1> => <table1> },
- [
- { <alias2> => <table2>, -join_type => 'inner|left|right' },
- [], # nested JOIN (optional)
- { <table1.column1> => <table2.column2>, ... (more conditions) },
- ],
- # More of the above [ ] may follow for additional joins
- ]
-
- <table1> <alias1>
- JOIN
- <table2> <alias2>
- [JOIN ...]
- ON <table1.column1> = <table2.column2>
- <more joins may follow>
-
-An easy way to follow the examples below is to remember the following:
-
- Anything inside "[]" is a JOIN
- Anything inside "{}" is a condition for the enclosing JOIN
-
-The following examples utilize a "person" table in a family tree application.
-In order to express parent->child relationships, this table is self-joined:
-
- # Person->belongs_to('father' => 'Person');
- # Person->belongs_to('mother' => 'Person');
-
-C<from> can be used to nest joins. Here we return all children with a father,
-then search against all mothers of those children:
-
- $rs = $schema->resultset('Person')->search(
- undef,
- {
- alias => 'mother', # alias columns in accordance with "from"
- from => [
- { mother => 'person' },
- [
- [
- { child => 'person' },
- [
- { father => 'person' },
- { 'father.person_id' => 'child.father_id' }
- ]
- ],
- { 'mother.person_id' => 'child.mother_id' }
- ],
- ]
- },
- );
-
- # Equivalent SQL:
- # SELECT mother.* FROM person mother
- # JOIN (
- # person child
- # JOIN person father
- # ON ( father.person_id = child.father_id )
- # )
- # ON ( mother.person_id = child.mother_id )
-
-The type of any join can be controlled manually. To search against only people
-with a father in the person table, we could explicitly use C<INNER JOIN>:
-
- $rs = $schema->resultset('Person')->search(
- undef,
- {
- alias => 'child', # alias columns in accordance with "from"
- from => [
- { child => 'person' },
- [
- { father => 'person', -join_type => 'inner' },
- { 'father.id' => 'child.father_id' }
- ],
- ]
- },
- );
-
- # Equivalent SQL:
- # SELECT child.* FROM person child
- # INNER JOIN person father ON child.father_id = father.id
-
-If you need to express really complex joins or you need a subselect, you
-can supply literal SQL to C<from> via a scalar reference. In this case
-the contents of the scalar will replace the table name asscoiated with the
-resultsource.
-
-WARNING: This technique might very well not work as expected on chained
-searches - you have been warned.
-
- # Assuming the Event resultsource is defined as:
-
- MySchema::Event->add_columns (
- sequence => {
- data_type => 'INT',
- is_auto_increment => 1,
- },
- location => {
- data_type => 'INT',
- },
- type => {
- data_type => 'INT',
- },
- );
- MySchema::Event->set_primary_key ('sequence');
-
- # This will get back the latest event for every location. The column
- # selector is still provided by DBIC, all we do is add a JOIN/WHERE
- # combo to limit the resultset
-
- $rs = $schema->resultset('Event');
- $table = $rs->result_source->name;
- $latest = $rs->search (
- undef,
- { from => \ "
- (SELECT e1.* FROM $table e1
- JOIN $table e2
- ON e1.location = e2.location
- AND e1.sequence < e2.sequence
- WHERE e2.sequence is NULL
- ) me",
- },
- );
-
- # Equivalent SQL (with the DBIC chunks added):
-
- SELECT me.sequence, me.location, me.type FROM
- (SELECT e1.* FROM events e1
- JOIN events e2
- ON e1.location = e2.location
- AND e1.sequence < e2.sequence
- WHERE e2.sequence is NULL
- ) me;
-
=head2 for
=over 4
projects / dbsrgits/DBIx-Class.git / blobdiff