如何在 DBIC 中找到未知数量的结果集的并集？

Question

您好，我正在使用 Helper::ResultSet::SetOperations 库来查找某些结果集的并集和交集。如果我知道结果集的数量，那么一切正常，但是我试图让它为未知数量的结果集工作。

处理 3 时以下工作 'devices'

my $firstdevice = shift @{$devices};
my $rs1 = $self->search({ 'devices.devicename' => $firstdevice },  {  join => { devicetype => 'devices' },  result_class => 'DBIx::Class::ResultClass::HashRefInflator' } ); 


my $seconddevice = shift @{$devices};
my $rs2 = $self->search({ 'devices.devicename' => $seconddevice },  {  join => { devicetype => 'devices' },result_class => 'DBIx::Class::ResultClass::HashRefInflator' }  );   

my $thirddevice= shift @{$devices};
my $rs3 = $self->search({ 'devices.devicename' => $thirddevice },  {  join => { devicetype => 'devices' },result_class => 'DBIx::Class::ResultClass::HashRefInflator' }  );            

my $data = [$rs1->union([$rs2, $rs3])->all];

但是，如果我尝试像下面这样处理未知数额，我会得到

Can't call method "result_class" on unblessed reference at /usr/local/share/perl/5.18.2/DBIx/Class/Helper/ResultSet/SetOperations.pm line 63.

当我运行:

my $data = [$rs1->union([@rslist])->all];

以下是我尝试让它工作的尝试：

#shift off the first device as we still need $rs1
my $firstdevice = shift @{$devices};
my $rs1 = $self->search({ 'devices.devicename' => $firstdevice },  {  join => { devicetype => 'devices' },  result_class => 'DBIx::Class::ResultClass::HashRefInflator' } ); 


my @rslist;

for my $device (@{$devices}) {
    push @rslist, $self->search({ 'devices.devicename' => $device },  {  join => { devicetype => 'devices' },  result_class => 'DBIx::Class::ResultClass::HashRefInflator' } );          
}

my $data = [$rs1->union([@rslist])->all];

Answer 1

当您将 ->search 的 return 值推送到列表上下文的 @rslist 时，搜索不会 return 一个结果集，而是一个结果对象列表，它们是哈希引用，因为HRI result_class。使用 search_rs 将解决您的问题。

由于 union 采用结果集的 arrayref，我将传递 \@rslist 而不是构建新的 arrayref。

如何在 DBIC 中找到未知数量的结果集的并集？

how to find the union of an unknown number of resultsets in DBIC?

mysql

perl

dbix-class