我是否需要為DBIx :: Class belongs_to關系手動創建索引

Question

我正在使用DBIx::Class模塊來實現我的應用程序的ORM方法。

我的人際關系有些問題。

我有以下內容

package MySchema::Result::ClusterIP;
use strict;
use warnings;

use base qw/DBIx::Class::Core/;

our $VERSION = '1.0';

__PACKAGE__->load_components(qw/InflateColumn::Object::Enum Core/);
__PACKAGE__->table('cluster_ip');

__PACKAGE__->add_columns( # Columns here );

__PACKAGE__->set_primary_key('objkey');
__PACKAGE__->belongs_to( 'configuration' => 'MySchema::Result::Configuration', 'config_key');
__PACKAGE__->belongs_to( 'cluster' => 'MySchema::Result::Cluster',
                            { 'foreign.config_key' => 'self.config_key',
                              'foreign.id'         => 'self.cluster_id'
                            }
                        );

以及

package MySchema::Result::Cluster;
use strict;
use warnings;

use base qw/DBIx::Class::Core/;

our $VERSION = '1.0';

__PACKAGE__->load_components(qw/InflateColumn::Object::Enum Core/);
__PACKAGE__->table('cluster');

__PACKAGE__->add_columns(  # Columns here );
__PACKAGE__->set_primary_key('objkey');
__PACKAGE__->belongs_to( 'configuration' => 'MySchema::Result::Configuration', 'config_key');
__PACKAGE__->has_many('cluster_ip'  => 'MySchema::Result::ClusterIP',
                            { 'foreign.config_key' => 'self.config_key',
                              'foreign.cluster_id' => 'self.id'
                            });

還有其他幾個模塊，但我不相信它們是相關的。

當我嘗試部署此架構時，出現以下錯誤：

DBIx::Class::Schema::deploy(): DBI Exception: DBD::mysql::db do failed: Can't create table 'test.cluster_ip' (errno: 150) [
for Statement "CREATE TABLE `cluster_ip` (
  `objkey` smallint(5) unsigned NOT NULL auto_increment,
  `config_key` smallint(5) unsigned NOT NULL,
  `cluster_id` char(16) NOT NULL,
  INDEX `cluster_ip_idx_config_key_cluster_id` (`config_key`, `cluster_id`),
  INDEX `cluster_ip_idx_config_key` (`config_key`),
  PRIMARY KEY (`objkey`),
  CONSTRAINT `cluster_ip_fk_config_key_cluster_id` FOREIGN KEY (`config_key`, `cluster_id`) REFERENCES `cluster` (`config_key`, `id`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `cluster_ip_fk_config_key` FOREIGN KEY (`config_key`) REFERENCES `configuration` (`config_key`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB"] at test_deploy.pl line 18

 (running "CREATE TABLE `cluster_ip` (
  `objkey` smallint(5) unsigned NOT NULL auto_increment,
  `config_key` smallint(5) unsigned NOT NULL,
  `cluster_id` char(16) NOT NULL,
  INDEX `cluster_ip_idx_config_key_cluster_id` (`config_key`, `cluster_id`),
  INDEX `cluster_ip_idx_config_key` (`config_key`),
  PRIMARY KEY (`objkey`),
  CONSTRAINT `cluster_ip_fk_config_key_cluster_id` FOREIGN KEY (`config_key`, `cluster_id`) REFERENC
ES `cluster` (`config_key`, `id`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `cluster_ip_fk_config_key` FOREIGN KEY (`config_key`) REFERENCES `configuration` (`conf
ig_key`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB") at test_deploy.pl line 18

據我所知，MySQL正在抱怨FOREIGN KEY約束，特別是cluster表中的（ config_key ， id ）REFERENCE。 從我閱讀MySQL文檔來看，這似乎是一個合理的抱怨，特別是關於本文檔頁面的第三個要點。

這是我的問題。 我在DBIx::Class模塊中遺漏了什么？ 我意識到我可以顯式創建必要的索引來匹配這個外鍵約束，但這似乎是重復的工作。 我是否應該采取措施使其隱含發生？

Answer 1

不確定這里發生了什么，因為SQL :: Translator :: Producer :: MySQL應該在部署的DDL的開頭插入SET foreign_key_checks=0 ，這樣就不會發生外鍵錯誤。 我懷疑即使在部署了整個DDL之后某些東西也被破壞了。 您可以通過連接到DB並運行此語句來找出外鍵錯誤的確切性質：

SHOW INNODB STATUS;

Answer 2

我剛剛通過將以下內容添加到導致問題的結果類中來解決了同樣的問題：

sub sqlt_deploy_hook {
   my ($self, $sqlt_table) = @_;
   $sqlt_table->add_index(name => 'idx_my_column', fields => ['my_column']);
}