=head1 NAME
-DBIx::Class::ResultSet - Responsible for fetching and creating resultset.
+DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
=head1 SYNOPSIS
- my $rs = $schema->resultset('User')->search({ registered => 1 });
- my @rows = $schema->resultset('CD')->search({ year => 2005 })->all();
+ my $users_rs = $schema->resultset('User');
+ my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
+ my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
=head1 DESCRIPTION
-The resultset is also known as an iterator. It is responsible for handling
-queries that may return an arbitrary number of rows, e.g. via L</search>
-or a C<has_many> relationship.
+A ResultSet is an object which stores a set of conditions representing
+a query. It is the backbone of DBIx::Class (i.e. the really
+important/useful bit).
-In the examples below, the following table classes are used:
+No SQL is executed on the database when a ResultSet is created, it
+just stores all the conditions needed to create the query.
- package MyApp::Schema::Artist;
- use base qw/DBIx::Class/;
- __PACKAGE__->load_components(qw/Core/);
- __PACKAGE__->table('artist');
- __PACKAGE__->add_columns(qw/artistid name/);
- __PACKAGE__->set_primary_key('artistid');
- __PACKAGE__->has_many(cds => 'MyApp::Schema::CD');
- 1;
+A basic ResultSet representing the data of an entire table is returned
+by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
+L<Source|DBIx::Class::Manual::Glossary/Source> name.
- package MyApp::Schema::CD;
- use base qw/DBIx::Class/;
- __PACKAGE__->load_components(qw/Core/);
- __PACKAGE__->table('cd');
- __PACKAGE__->add_columns(qw/cdid artist title year/);
- __PACKAGE__->set_primary_key('cdid');
- __PACKAGE__->belongs_to(artist => 'MyApp::Schema::Artist');
- 1;
+ my $users_rs = $schema->resultset('User');
+
+A new ResultSet is returned from calling L</search> on an existing
+ResultSet. The new one will contain all the conditions of the
+original, plus any new conditions added in the C<search> call.
+
+A ResultSet is also an iterator. L</next> is used to return all the
+L<DBIx::Class::Row>s the ResultSet represents.
+
+The query that the ResultSet represents is B<only> executed against
+the database when these methods are called:
+
+=over
+
+=item L</find>
+
+=item L</next>
+
+=item L</all>
+
+=item L</count>
+
+=item L</single>
+
+=item L</first>
+
+=back
+
+=head1 EXAMPLES
+
+=head2 Chaining resultsets
+
+Let's say you've got a query that needs to be run to return some data
+to the user. But, you have an authorization system in place that
+prevents certain users from seeing certain information. So, you want
+to construct the basic query in one method, but add constraints to it in
+another.
+
+ sub get_data {
+ my $self = shift;
+ my $request = $self->get_request; # Get a request object somehow.
+ my $schema = $self->get_schema; # Get the DBIC schema object somehow.
+
+ my $cd_rs = $schema->resultset('CD')->search({
+ title => $request->param('title'),
+ year => $request->param('year'),
+ });
+
+ $self->apply_security_policy( $cd_rs );
+
+ return $cd_rs->all();
+ }
+
+ sub apply_security_policy {
+ my $self = shift;
+ my ($rs) = @_;
+
+ return $rs->search({
+ subversive => 0,
+ });
+ }
+
+=head2 Multiple queries
+
+Since a resultset just defines a query, you can do all sorts of
+things with it with the same object.
+
+ # Don't hit the DB yet.
+ my $cd_rs = $schema->resultset('CD')->search({
+ title => 'something',
+ year => 2009,
+ });
+
+ # Each of these hits the DB individually.
+ my $count = $cd_rs->count;
+ my $most_recent = $cd_rs->get_column('date_released')->max();
+ my @records = $cd_rs->all;
+
+And it's not just limited to SELECT statements.
+
+ $cd_rs->delete();
+
+This is even cooler:
+
+ $cd_rs->create({ artist => 'Fred' });
+
+Which is the same as:
+
+ $schema->resultset('CD')->create({
+ title => 'something',
+ year => 2009,
+ artist => 'Fred'
+ });
+
+See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
=head1 OVERLOADING
sub single {
my ($self, $where) = @_;
+ if(@_ > 2) {
+ $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
+ }
+
my $attrs = { %{$self->_resolved_attrs} };
if ($where) {
if (defined $attrs->{where}) {
$cd_rs = $rs->search_like({ title => '%blue%'});
Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
-that this is simply a convenience method. You most likely want to use
-L</search> with specific operators.
+that this is simply a convenience method retained for ex Class::DBI users.
+You most likely want to use L</search> with specific operators.
For more information, see L<DBIx::Class::Manual::Cookbook>.
=cut
sub all {
- my ($self) = @_;
+ my $self = shift;
+ if(@_) {
+ $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
+ }
+
return @{ $self->get_cache } if $self->get_cache;
my @obj;
$self->throw_exception("Values for update must be a hash")
unless ref $values eq 'HASH';
+ carp( 'WARNING! Currently $rs->update() does not generate proper SQL'
+ . ' on joined resultsets, and may affect 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;
return $self->result_source->storage->update(
=head2 _normalize_populate_args ($args)
-Private method used by L</populate> to normalize it's incoming arguments. Factored
+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.
defined $self->{cond}
&& $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
) {
- %new = %{$self->{attrs}{related_objects}};
+ %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
+ $new{-from_resultset} = [ keys %new ] if keys %new;
} else {
$self->throw_exception(
"Can't abstract implicit construct, condition not a hash"
return \%unaliased;
}
+=head2 as_query
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: \[ $sql, @bind ]
+
+=back
+
+Returns the SQL query and bind vars associated with the invocant.
+
+This is generally used as the RHS for a subquery.
+
+=cut
+
+sub as_query { return shift->cursor->as_query(@_) }
+
=head2 find_or_new
=over 4
$cd->cd_to_producer->find_or_new({ producer => $producer },
{ key => 'primary });
-Find an existing record from this resultset, based on it's primary
+Find an existing record from this resultset, based on its 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<DBIx::Class::Row/insert> on it.
pairs representing the columns of the table and the values you wish to
store. If the appropriate relationships are set up, foreign key fields
can also be passed an object representing the foreign row, and the
-value will be set to it's primary key.
+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>),
$person_rs->create({
name=>"Some Person",
- email=>"somebody@someplace.com"
+ email=>"somebody@someplace.com"
});
Example of creating a new row and also creating rows in a related C<has_many>
$cd_rs->create({
title=>"Music for Silly Walks",
- year=>2000,
- artist => {
- name=>"Silly Musician",
- }
+ year=>2000,
+ artist => {
+ name=>"Silly Musician",
+ }
});
=cut
};
}
+=head2 current_source_alias
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $source_alias
+
+=back
+
+Returns the current table alias for the result source this resultset is built
+on, that will be used in the SQL query. Usually it is C<me>.
+
+Currently the source alias that refers to the result set returned by a
+L</search>/L</find> family method depends on how you got to the resultset: it's
+C<me> by default, but eg. L</search_related> aliases it to the related result
+source name (and keeps C<me> referring to the original result set). The long
+term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
+(and make this method unnecessary).
+
+Thus it's currently necessary to use this method in predefined queries (see
+L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
+source alias of the current result set:
+
+ # in a result set class
+ sub modified_by {
+ my ($self, $user) = @_;
+
+ my $me = $self->current_source_alias;
+
+ return $self->search(
+ "$me.modified" => $user->id,
+ );
+ }
+
+=cut
+
+sub current_source_alias {
+ my ($self) = @_;
+
+ return ($self->{attrs} || {})->{alias} || 'me';
+}
+
sub _resolve_from {
my ($self, $extra_join) = @_;
my $source = $self->result_source;
my $self = shift;
return $self->{_attrs} if $self->{_attrs};
- my $attrs = { %{$self->{attrs}||{}} };
+ my $attrs = { %{ $self->{attrs} || {} } };
my $source = $self->result_source;
- my $alias = $attrs->{alias};
+ my $alias = $attrs->{alias};
$attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
- if ($attrs->{columns}) {
- delete $attrs->{as};
- } elsif (!$attrs->{select}) {
- $attrs->{columns} = [ $source->columns ];
+ my @colbits;
+
+ # 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 );
}
-
- $attrs->{select} =
- ($attrs->{select}
- ? (ref $attrs->{select} eq 'ARRAY'
- ? [ @{$attrs->{select}} ]
- : [ $attrs->{select} ])
- : [ map { m/\./ ? $_ : "${alias}.$_" } @{delete $attrs->{columns}} ]
- );
- $attrs->{as} =
- ($attrs->{as}
- ? (ref $attrs->{as} eq 'ARRAY'
- ? [ @{$attrs->{as}} ]
- : [ $attrs->{as} ])
- : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{$attrs->{select}} ]
+ # 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 ( $attrs->{$_} );
+ }
+
+ # start with initial select items
+ if ( $attrs->{select} ) {
+ $attrs->{select} =
+ ( ref $attrs->{select} eq 'ARRAY' )
+ ? [ @{ $attrs->{select} } ]
+ : [ $attrs->{select} ];
+ $attrs->{as} = (
+ $attrs->{as}
+ ? (
+ ref $attrs->{as} eq 'ARRAY'
+ ? [ @{ $attrs->{as} } ]
+ : [ $attrs->{as} ]
+ )
+ : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
);
-
- my $adds;
- if ($adds = delete $attrs->{include_columns}) {
- $adds = [$adds] unless ref $adds eq 'ARRAY';
- push(@{$attrs->{select}}, @$adds);
- push(@{$attrs->{as}}, map { m/([^.]+)$/; $1 } @$adds);
}
- if ($adds = delete $attrs->{'+select'}) {
+ else {
+
+ # otherwise we intialise select & as to empty
+ $attrs->{select} = [];
+ $attrs->{as} = [];
+ }
+
+ # now add colbits to select/as
+ push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
+ push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
+
+ my $adds;
+ if ( $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 (my $adds = delete $attrs->{'+as'}) {
+ if ( $adds = delete $attrs->{'+as'} ) {
$adds = [$adds] unless ref $adds eq 'ARRAY';
- push(@{$attrs->{as}}, @$adds);
+ push( @{ $attrs->{as} }, @$adds );
}
- $attrs->{from} ||= [ { 'me' => $source->from } ];
+ $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
- if (exists $attrs->{join} || exists $attrs->{prefetch}) {
+ if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
my $join = delete $attrs->{join} || {};
- if (defined $attrs->{prefetch}) {
- $join = $self->_merge_attr(
- $join, $attrs->{prefetch}
- );
-
+ if ( defined $attrs->{prefetch} ) {
+ $join = $self->_merge_attr( $join, $attrs->{prefetch} );
+
}
- $attrs->{from} = # have to copy here to avoid corrupting the original
+ $attrs->{from} = # have to copy here to avoid corrupting the original
[
- @{$attrs->{from}},
- $source->resolve_join($join, $alias, { %{$attrs->{seen_join}||{}} })
+ @{ $attrs->{from} },
+ $source->resolve_join(
+ $join, $alias, { %{ $attrs->{seen_join} || {} } }
+ )
];
}
- $attrs->{group_by} ||= $attrs->{select} if delete $attrs->{distinct};
- if ($attrs->{order_by}) {
- $attrs->{order_by} = (ref($attrs->{order_by}) eq 'ARRAY'
- ? [ @{$attrs->{order_by}} ]
- : [ $attrs->{order_by} ]);
- } else {
- $attrs->{order_by} = [];
+ $attrs->{group_by} ||= $attrs->{select}
+ if delete $attrs->{distinct};
+ if ( $attrs->{order_by} ) {
+ $attrs->{order_by} = (
+ ref( $attrs->{order_by} ) eq 'ARRAY'
+ ? [ @{ $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);
+ if ( my $prefetch = delete $attrs->{prefetch} ) {
+ $prefetch = $self->_merge_attr( {}, $prefetch );
my @pre_order;
- my $seen = $attrs->{seen_join} || {};
- foreach my $p (ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch)) {
+ my $seen = { %{ $attrs->{seen_join} || {} } };
+ foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
+
# bring joins back to level of current class
- my @prefetch = $source->resolve_prefetch(
- $p, $alias, $seen, \@pre_order, $collapse
- );
- push(@{$attrs->{select}}, map { $_->[0] } @prefetch);
- push(@{$attrs->{as}}, map { $_->[1] } @prefetch);
+ my @prefetch =
+ $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
+ push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
+ push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
}
- push(@{$attrs->{order_by}}, @pre_order);
+ push( @{ $attrs->{order_by} }, @pre_order );
}
$attrs->{collapse} = $collapse;
- if ($attrs->{page}) {
+ if ( $attrs->{page} ) {
$attrs->{offset} ||= 0;
- $attrs->{offset} += ($attrs->{rows} * ($attrs->{page} - 1));
+ $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
}
return $self->{_attrs} = $attrs;
=head1 ATTRIBUTES
-The resultset takes various attributes that modify its behavior. Here's an
-overview of them:
+Attributes are used to refine a ResultSet in various ways when
+searching for data. They can be passed to any method which takes an
+C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
+L</count>.
+
+These are in no particular order:
=head2 order_by
=over 4
-=item Value: ($order_by | \@order_by)
+=item Value: ( $order_by | \@order_by | \%order_by )
=back
-Which column(s) to order the results by. This is currently passed
-through directly to SQL, so you can give e.g. C<year DESC> for a
-descending order on the column `year'.
+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:
+
+ For descending order:
+
+ order_by => { -desc => [qw/col1 col2 col3/] }
+
+ For explicit ascending order:
-Please note that if you have C<quote_char> enabled (see
-L<DBIx::Class::Storage::DBI/connect_info>) you will need to do C<\'year DESC' > to
-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.)
+ order_by => { -asc => 'col' }
+
+The old scalarref syntax (i.e. order_by => \'year DESC') is still
+supported, although you are strongly encouraged to use the hashref
+syntax as outlined above.
=head2 columns
=back
-Shortcut to request a particular set of columns to be retrieved. Adds
-C<me.> onto the start of any column without a C<.> in it and sets C<select>
-from that, then auto-populates C<as> from C<select> as normal. (You may also
-use the C<cols> attribute, as in earlier versions of DBIC.)
+Shortcut to request a particular set of columns to be retrieved. Each
+column spec may be a string (a table column name), or a hash (in which
+case the key is the C<as> value, and the value is used as the C<select>
+expression). Adds C<me.> onto the start of any column without a C<.> in
+it and sets C<select> from that, then auto-populates C<as> from
+C<select> as normal. (You may also use the C<cols> attribute, as in
+earlier versions of DBIC.)
-=head2 include_columns
+=head2 +columns
=over 4
=back
-Shortcut to include additional columns in the returned results - for example
+Indicates additional columns to be selected from storage. Works the same
+as L</columns> but adds columns to the selection. (You may also use the
+C<include_columns> attribute, as in earlier versions of DBIC). For
+example:-
$schema->resultset('CD')->search(undef, {
- include_columns => ['artist.name'],
+ '+columns' => ['artist.name'],
join => ['artist']
});
column (or relationship) accessor, and 'name' is the name of the column
accessor in the related table.
+=head2 include_columns
+
+=over 4
+
+=item Value: \@columns
+
+=back
+
+Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
+
=head2 select
=over 4
=over 4
-Indicates additional column names for those added via L</+select>.
+Indicates additional column names for those added via L</+select>. See L</as>.
=back