动态地将列添加到 DBIx::Class ResultSet

发布于 2024-10-05 21:19:32 字数 283 浏览 0 评论 0原文

我有一个代表 eBay 拍卖的 DBIx::Class 对象。基础表有一个描述列，其中包含大量数据。描述列几乎从未使用过，因此它不包含在该表的 DBIx::Class 列列表中。这样，大多数查询就不会获取拍卖描述数据。

不过，我确实有一个脚本需要本专栏。在这种情况下，我想像访问任何其他列一样访问描述列的内容：

$auction->description

如何在不强制所有其他查询获取描述列的情况下完成此操作？

原文

I have a DBIx::Class object representing an eBay auction. The underlying table has a description column which contains a lot of data. The description column is almost never used, so it's not included in the DBIx::Class column list for that table. That way, most queries don't fetch the auction description data.

I do, however, have one script that needs this column. In this one case, I want to access the contents of the description column as I would any other column:

$auction->description

How can I accomplish this without forcing all other queries to fetch the description column?

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你げ笑在眉眼 2024-10-12 21:19:32

在旧版本的 DBIx::Class 中（不确定版本号），以下内容曾经有效：

my $rs = $schema->resultset('Auctions');
my $lots = $rs->search(
   undef,
   { '+select' => 'description', '+as' => 'description' },
);

这似乎不适用于现代版本的 DBIx:: 下的行更新：类。尝试在 DBIx::Class 0.08123 下进行更新

$auction->update({ description => '...'})

会出现以下错误：“DBIx::Class::Relationship::CascadeActions::update(): No such column description at ...”

假设需要额外列的脚本正在其自己的进程中运行。你可以这样做：

my $rs = $schema->resultset('Auctions');
$rs->result_source->add_columns('description');
YourApp::Schema::Lots->add_columns('description');
YourApp::Schema::Lots->register_column('description');

当然，这是一个全球性的变化。添加该列后，同一进程中的其他代码将开始在查询中获取 description 列。更不用说，它有点丑陋。

In older versions of DBIx::Class (not sure of the version number), the following used to work:

my $rs = $schema->resultset('Auctions');
my $lots = $rs->search(
   undef,
   { '+select' => 'description', '+as' => 'description' },
);

That doesn't seem to work for row updates under modern versions of DBIx::Class. Trying that with an update

$auction->update({ description => '...'})

under DBIx::Class 0.08123 gives the following error: "DBIx::Class::Relationship::CascadeActions::update(): No such column description at ..."

Assuming that the script needing the extra column is running in its own process. You can do something like this:

my $rs = $schema->resultset('Auctions');
$rs->result_source->add_columns('description');
YourApp::Schema::Lots->add_columns('description');
YourApp::Schema::Lots->register_column('description');

Of course, that's a global change. After adding the column, other code in the same process will start fetching the description column in queries. Not to mention, it's kind of ugly.

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