X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultSet.pm;h=3b68af1d7a1f5d4aaf19f0c90e9f06b56858321f;hb=2baa36f491033fadc057fc0d1be2256200281e9c;hp=7097d648133d354b568015083702a12816c1fc6d;hpb=8273e845426f0187b4ad6c4a1b42286fa09a648f;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm index 7097d64..3b68af1 100644 --- a/lib/DBIx/Class/ResultSet.pm +++ b/lib/DBIx/Class/ResultSet.pm @@ -74,6 +74,34 @@ However, if it is used in a boolean context it is B true. So if you want to check if a resultset has any results, you must use C. +=head1 CUSTOM ResultSet CLASSES THAT USE Moose + +If you want to make your custom ResultSet classes with L, use a template +similar to: + + package MyApp::Schema::ResultSet::User; + + use Moose; + use namespace::autoclean; + use MooseX::NonMoose; + extends 'DBIx::Class::ResultSet'; + + sub BUILDARGS { $_[2] } + + ...your code... + + __PACKAGE__->meta->make_immutable; + + 1; + +The L is necessary so that the L constructor does not +clash with the regular ResultSet constructor. Alternatively, you can use: + + __PACKAGE__->meta->make_immutable(inline_constructor => 0); + +The L is necessary because the +signature of the ResultSet C is C<< ->new($source, \%args) >>. + =head1 EXAMPLES =head2 Chaining resultsets @@ -265,7 +293,7 @@ condition-bound methods L, L and L. The user must ensure manually that any value passed to this method will stringify to something the RDBMS knows how to deal with. A notable example is the handling of L objects, for more info see: -L. +L. =cut @@ -899,7 +927,7 @@ sub _build_unique_cond { =over 4 -=item Arguments: $rel, $cond, \%attrs? +=item Arguments: $rel, $cond?, \%attrs? =item Return Value: $new_resultset (scalar context) || @row_objs (list context) @@ -1513,10 +1541,15 @@ sub _count_subq_rs { # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it delete @{$sub_attrs}{qw/collapse columns as select _prefetch_selector_range order_by for/}; - # if we multi-prefetch we group_by primary keys only as this is what we would + # if we multi-prefetch we group_by something unique, 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) ] + $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{ + $rsrc->_identifying_column_set || $self->throw_exception( + 'Unable to construct a unique group_by criteria properly collapsing the ' + . 'has_many prefetch before count()' + ); + } ] } # Calculate subquery selector @@ -1709,35 +1742,122 @@ sub first { sub _rs_update_delete { my ($self, $op, $values) = @_; + my $cond = $self->{cond}; my $rsrc = $self->result_source; + my $storage = $rsrc->schema->storage; + + my $attrs = { %{$self->_resolved_attrs} }; + + # "needs" is a strong word here - if the subquery is part of an IN clause - no point of + # even adding the group_by. It will really be used only when composing a poor-man's + # multicolumn-IN equivalent OR set + my $needs_group_by_subq = defined $attrs->{group_by}; + + # simplify the joinmap and maybe decide if a grouping (and thus subquery) is necessary + my $relation_classifications; + if (ref($attrs->{from}) eq 'ARRAY') { + $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $cond, $attrs); + + $relation_classifications = $storage->_resolve_aliastypes_from_select_args ( + [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ], + $attrs->{select}, + $cond, + $attrs + ) unless $needs_group_by_subq; # we already know we need a group, no point of resolving them + } + else { + $needs_group_by_subq ||= 1; # if {from} is unparseable assume the worst + } - my $needs_group_by_subq = $self->_has_resolved_attr (qw/collapse group_by -join/); - my $needs_subq = $needs_group_by_subq || $self->_has_resolved_attr(qw/rows offset/); + $needs_group_by_subq ||= exists $relation_classifications->{multiplying}; + + # if no subquery - life is easy-ish + unless ( + $needs_group_by_subq + or + keys %$relation_classifications # if any joins at all - need to wrap a subq + or + $self->_has_resolved_attr(qw/rows offset/) # limits call for a subq + ) { + # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus + # a condition containing 'me' or other table prefixes will not work + # at all. What this code tries to do (badly) is to generate a condition + # with the qualifiers removed, by exploiting the quote mechanism of sqla + # + # this is atrocious and should be replaced by normal sqla introspection + # one sunny day + my ($sql, @bind) = do { + my $sqla = $rsrc->storage->sql_maker; + local $sqla->{_dequalify_idents} = 1; + $sqla->_recurse_where($self->{cond}); + } if $self->{cond}; - if ($needs_group_by_subq or $needs_subq) { + return $rsrc->storage->$op( + $rsrc, + $op eq 'update' ? $values : (), + $self->{cond} ? \[$sql, @bind] : (), + ); + } - # make a new $rs selecting only the PKs (that's all we really need) - my $attrs = $self->_resolved_attrs_copy; + # we got this far - means it is time to wrap a subquery + my $idcols = $rsrc->_identifying_column_set || $self->throw_exception( + sprintf( + "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'", + $op, + $rsrc->source_name, + ) + ); + my $existing_group_by = delete $attrs->{group_by}; + # make a new $rs selecting only the PKs (that's all we really need for the subq) + delete $attrs->{$_} for qw/collapse _collapse_order_by select _prefetch_selector_range as/; + $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ]; + $attrs->{group_by} = \ ''; # FIXME - this is an evil hack, it causes the optimiser to kick in and throw away the LEFT joins + my $subrs = (ref $self)->new($rsrc, $attrs); - delete $attrs->{$_} for qw/collapse _collapse_order_by select _prefetch_selector_range as/; - $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->_pri_cols) ]; + if (@$idcols == 1) { + return $storage->$op ( + $rsrc, + $op eq 'update' ? $values : (), + { $idcols->[0] => { -in => $subrs->as_query } }, + ); + } + elsif ($storage->_use_multicolumn_in) { + # This is hideously ugly, but SQLA does not understand multicol IN expressions + my $sql_maker = $storage->sql_maker; + my ($sql, @bind) = @${$subrs->as_query}; + $sql = sprintf ('(%s) IN %s', # the as_query already comes with a set of parenthesis + join (', ', map { $sql_maker->_quote ($_) } @$idcols), + $sql, + ); + return $storage->$op ( + $rsrc, + $op eq 'update' ? $values : (), + \[$sql, @bind], + ); + } + else { + # if all else fails - get all primary keys and operate over a ORed set + # wrap in a transaction for consistency + # this is where the group_by starts to matter + my $subq_group_by; if ($needs_group_by_subq) { - # make sure no group_by was supplied, or if there is one - make sure it matches - # the columns compiled above perfectly. Anything else can not be sanely executed - # on most databases so croak right then and there + $subq_group_by = $attrs->{columns}; - if (my $g = $attrs->{group_by}) { + # make sure if there is a supplied group_by it matches the columns compiled above + # perfectly. Anything else can not be sanely executed on most databases so croak + # right then and there + if ($existing_group_by) { my @current_group_by = map { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" } - @$g + @$existing_group_by ; if ( join ("\x00", sort @current_group_by) ne - join ("\x00", sort @{$attrs->{columns}} ) + join ("\x00", sort @$subq_group_by ) ) { $self->throw_exception ( "You have just attempted a $op operation on a resultset which does group_by" @@ -1748,33 +1868,27 @@ sub _rs_update_delete { ); } } - else { - $attrs->{group_by} = $attrs->{columns}; - } } - my $subrs = (ref $self)->new($rsrc, $attrs); - return $self->result_source->storage->_subq_update_delete($subrs, $op, $values); - } - else { - # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus - # a condition containing 'me' or other table prefixes will not work - # at all. What this code tries to do (badly) is to generate a condition - # with the qualifiers removed, by exploiting the quote mechanism of sqla - # - # this is atrocious and should be replaced by normal sqla introspection - # one sunny day - my ($sql, @bind) = do { - my $sqla = $rsrc->storage->sql_maker; - local $sqla->{_dequalify_idents} = 1; - $sqla->_recurse_where($self->{cond}); - } if $self->{cond}; + my $guard = $storage->txn_scope_guard; - return $rsrc->storage->$op( + my @op_condition; + for my $row ($subrs->search({}, { group_by => $subq_group_by })->cursor->all) { + push @op_condition, { map + { $idcols->[$_] => $row->[$_] } + (0 .. $#$idcols) + }; + } + + my $res = $storage->$op ( $rsrc, $op eq 'update' ? $values : (), - $self->{cond} ? \[$sql, @bind] : (), + \@op_condition, ); + + $guard->commit; + + return $res; } } @@ -1794,7 +1908,7 @@ triggers, nor will it update any row object instances derived from this resultset (this includes the contents of the L if any). See L if you need to execute any on-update triggers or cascades defined either by you or a -L. +L. The return value is a pass through of what the underlying storage backend returned, and may vary. See L for the most @@ -1807,7 +1921,7 @@ This is unlike the corresponding L. The user must ensure manually that any value passed to this method will stringify to something the RDBMS knows how to deal with. A notable example is the handling of L objects, for more info see: -L. +L. =cut @@ -1862,7 +1976,7 @@ L status of any row object instances derived from this resultset (this includes the contents of the L if any). See L if you need to execute any on-delete triggers or cascades defined either by you or a -L. +L. The return value is a pass through of what the underlying storage backend returned, and may vary. See L for the most common case. @@ -2598,6 +2712,23 @@ all in the call to C, even when set to C. See also L and L. For information on how to declare unique constraints, see L. +If you need to know if an existing row was found or a new one created use +L and L instead. Don't forget +to call L to save the newly created row to the +database! + + my $cd = $schema->resultset('CD')->find_or_new({ + cdid => 5, + artist => 'Massive Attack', + title => 'Mezzanine', + year => 2005, + }); + + if( $cd->in_storage ) { + # do some stuff + $cd->insert; + } + =cut sub find_or_create { @@ -2659,6 +2790,25 @@ all in the call to C, even when set to C. See also L and L. For information on how to declare unique constraints, see L. +If you need to know if an existing row was updated or a new one created use +L and L instead. Don't forget +to call L to save the newly created row to the +database! + + my $cd = $schema->resultset('CD')->update_or_new( + { + artist => 'Massive Attack', + title => 'Mezzanine', + year => 1998, + }, + { key => 'cd_artist_title' } + ); + + if( $cd->in_storage ) { + # do some stuff + $cd->insert; + } + =cut sub update_or_create { @@ -4134,6 +4284,8 @@ Adds to the WHERE clause. Can be overridden by passing C<< { where => undef } >> as an attribute to a resultset. +For more complicated where clauses see L. + =back =head2 cache