Question

当我运行代码时：

  return  $self->result_source->schema->resultset('Locality')->search(
      {
        'addresses_view.usage' => 0
        ,'me.id' => $self->id
      }
      ,{
        join => { servers => 'addresses_view' }
      }
    );

生成的下一个sql查询：

SELECT 
  "me"."id", "me"."active", "me"."priority", 
  "me"."country_id", "me"."name"
FROM "localities" "me"
LEFT JOIN "servers" "servers" ON "servers"."locality_id" = "me"."id" 
LEFT JOIN "pool_addresses_view" "addresses_view" ON "addresses_view"."server_id" = "servers"."id" 
WHERE ( ( "addresses_view"."usage" = ? AND "me"."id" = ? ) )

并且执行正常。

但是当我想要将列添加到＆＃39; SELECT＆＃39;

时

    ,'+columns' => [ 'addresses_view.ip', 'addresses_view.id' ]

我收到错误：Manual prefetch (via select/columns) not supported with accessor 'multi'

我在www.mail-archive.com/dbix-class@找到了同样的问题，但我不明白如何将columns属性传递给search_related以限制列选择

有没有办法将列添加到＆＃39; SELECT＆＃39;条款？

Answer 1

DBIx::Class::ResultSet#prefetch只是在内部填充连接和列属性的糖。

DBIx::Class::Manual::Joining包含大量有用的信息，说明可能的内容以及应该如何回答您的问题。

为什么手动预取（通过选择/列）不支持访问者＆＃39;多＆＃39;？

1 个答案: