学说2：如何在不丢失数据的情况下将一对多转换为多对多

Question

在我的应用程序中，我想在不丢失数据的情况下将一对多转换为多对多：

从：

/**
 * @ORM\ManyToOne(targetEntity="\AppBundle\Entity\FoodAnalytics\Recipe", inversedBy="medias")
 * @ORM\JoinColumn(name="recipeId", referencedColumnName="id", onDelete="CASCADE")
 */
protected $recipe;

至：

/**
 * @ORM\ManyToMany(targetEntity="\AppBundle\Entity\FoodAnalytics\Recipe", inversedBy="medias")
 * @ORM\JoinTable(
 *     name="media_recipes",
 *     joinColumns={@ORM\JoinColumn(name="mediaId", referencedColumnName="id", onDelete="CASCADE")},
 *     inverseJoinColumns={@ORM\JoinColumn(name="recipeId", referencedColumnName="id", onDelete="CASCADE")}
 * )
 */
protected $recipes;

当我转储我的学说 shema 更新时，它说它将删除数据，而不是我想要的：

CREATE TABLE media_recipes (mediaId INT UNSIGNED NOT NULL, recipeId INT UNSIGNED NOT NULL, INDEX IDX_C2BE64FC27D9F5AC (mediaId), INDEX IDX_C2BE64FC6DCBA54 (recipeId), PRIMARY KEY(mediaId, recipeId)) DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci ENGINE = InnoDB;
ALTER TABLE media_recipes ADD CONSTRAINT FK_C2BE64FC27D9F5AC FOREIGN KEY (mediaId) REFERENCES media (id) ON DELETE CASCADE;
ALTER TABLE media_recipes ADD CONSTRAINT FK_C2BE64FC6DCBA54 FOREIGN KEY (recipeId) REFERENCES Recipe (id) ON DELETE CASCADE;
ALTER TABLE media DROP FOREIGN KEY FK_6A2CA10C6DCBA54;
DROP INDEX IDX_6A2CA10C6DCBA54 ON media;
ALTER TABLE media DROP recipeId;

Process finished with exit code 0 at 13:04:46.
Execution time: 5 003 ms.

我该如何解决这个问题？ 即是否将配方表的先前 mysql mediaId 列与配方 ID 一起添加到新的 media_recipe 表中？

Answer 1

好的，我确实找到了一种使用学说迁移的方法。

我首先使用一个学说：模式：更新 --force 确保我的更改设置正确，检查分析器，然后恢复到最后一个数据库。

所以使用学说迁移捆绑：

doctrine:migrations:diff

创建一个新的迁移类

编辑类以满足您的需要。 我的是：

<?php

namespace Application\Migrations;

use AppBundle\Entity\Core\Media;
use AppBundle\Entity\FoodAnalytics\Recipe;
use Doctrine\DBAL\Migrations\AbstractMigration;
use Doctrine\DBAL\Schema\Schema;
use Symfony\Component\DependencyInjection\Container;
use Symfony\Component\DependencyInjection\ContainerAwareInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Auto-generated Migration: Please modify to your needs!
 */
class Version20150525154902 extends AbstractMigration implements ContainerAwareInterface
{

    private $customSQL = array();

    /** @var Container */
    private $container;


    public function setContainer(ContainerInterface $container = null)
    {
        $this->container = $container;
    }

    /**
     * @param Schema $schema
     */
    public function preUp(Schema $schema)
    {
        $query = "SELECT id as mediaId, recipeId FROM `media` WHERE recipeId IS NOT NULL";
        $data = $this->connection->prepare($query);
        $data->execute();
        foreach ($data as $row)
        {
            $mediaId = $row['mediaId'];
            $recipeId = $row['recipeId'];
            $this->customSQL[] = "($mediaId, $recipeId)";
        }

    }

    /**
     * @param Schema $schema
     */
    public function up(Schema $schema)
    {
        // this up() migration is auto-generated, please modify it to your needs
        $this->abortIf($this->connection->getDatabasePlatform()->getName() != 'mysql', 'Migration can only be executed safely on \'mysql\'.');

        $this->addSql('CREATE TABLE media_recipes (mediaId INT UNSIGNED NOT NULL, recipeId INT UNSIGNED NOT NULL, INDEX IDX_C2BE64FC27D9F5AC (mediaId), INDEX IDX_C2BE64FC6DCBA54 (recipeId), PRIMARY KEY(mediaId, recipeId)) DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci ENGINE = InnoDB');
        $this->addSql('ALTER TABLE media_recipes ADD CONSTRAINT FK_C2BE64FC27D9F5AC FOREIGN KEY (mediaId) REFERENCES media (id) ON DELETE CASCADE');
        $this->addSql('ALTER TABLE media_recipes ADD CONSTRAINT FK_C2BE64FC6DCBA54 FOREIGN KEY (recipeId) REFERENCES Recipe (id) ON DELETE CASCADE');
        $this->addSql('ALTER TABLE media DROP FOREIGN KEY FK_6A2CA10C6DCBA54');
        $this->addSql('DROP INDEX IDX_6A2CA10C6DCBA54 ON media');
        $this->addSql('ALTER TABLE media DROP recipeId');
        $this->addSql('ALTER TABLE recipe ADD versionDetails VARCHAR(200) DEFAULT NULL');

    }

    public function postUp(Schema $schema)
    {
        $SQL = 'INSERT INTO media_recipes (mediaId, recipeId) VALUES ' . implode(', ', $this->customSQL);

        $this->connection->executeQuery($SQL);
    }



    /**
     * @param Schema $schema
     */
    public function down(Schema $schema)
    {
        // this down() migration is auto-generated, please modify it to your needs
        $this->abortIf($this->connection->getDatabasePlatform()->getName() != 'mysql', 'Migration can only be executed safely on \'mysql\'.');

        $this->addSql('DROP TABLE media_recipes');
        $this->addSql('ALTER TABLE media ADD recipeId INT UNSIGNED DEFAULT NULL');
        $this->addSql('ALTER TABLE media ADD CONSTRAINT FK_6A2CA10C6DCBA54 FOREIGN KEY (recipeId) REFERENCES recipe (id) ON DELETE CASCADE');
        $this->addSql('CREATE INDEX IDX_6A2CA10C6DCBA54 ON media (recipeId)');
    }
}

然后执行更新：

doctrine:migrations:migrate

并确认y

Answer 2

我通过简单地使用php bin/console make:migration生成迁移来解决这个问题，然后使用 INSERT 语句扩展迁移，该语句在删除旧列之前将旧 oneToMany 字段中的所有数据复制到新的 manyToMany 表中。

为了坚持问题中的媒体/食谱示例，我将在$this->addSql('ALTER TABLE media DROP recipeId');之前添加这一行。 生成迁移中的行：

$this->addSql('INSERT INTO media_recipes (mediaId, recipeId) SELECT id, recipeId FROM media WHERE recipeId IS NOT NULL');

Answer 3

如果您想继续使用orm:schema-tool:update --force而不是采用doctrine:migrations:migrate ，那么您可以使用两步过程将关系从多对一迁移到多对多。

1. 创建many-to-many-step1分支
   • 在旧的 @ManyToOne/@JoinColumn/@OneToMany 属性和访问器旁边添加新的 @ManyToMany/@JoinTable 属性和访问器
   • 部署代码并运行orm:schema-tool:update --force
   • 使用INSERT INTO ... SELECT语句用旧的连接列内容填充新连接表
2. 创建many-to-many-step2分支
   • 更改代码以使用新的多对多关系和访问器
   • 删除旧的多对一关系的所有工件
   • 部署代码并运行orm:schema-tool:update --force

Answer 4

一种简单的方法是使用以下命令删除该列的唯一约束：

ALTER TABLE relation_table DROP INDEX UK_constraint_id;

如果您安装了 MySql Workbench，那就更容易了，因为您不需要发现约束 id。 只需选择您的表 -> 更改表并取消选中该列的 UQ 复选框，然后单击“应用”。

如果您没有安装 MySql Workbench，您可以执行以下查询以找出约束 id：

USE INFORMATION_SCHEMA;
SELECT TABLE_NAME,
       COLUMN_NAME,
       CONSTRAINT_NAME,
       REFERENCED_TABLE_NAME,
       REFERENCED_COLUMN_NAME
FROM KEY_COLUMN_USAGE
WHERE TABLE_SCHEMA = "<schema_name>" 
      AND TABLE_NAME = "<table_name>";

并且只需使用上面提到的 ALTER TABLE。