在 Laravel 6 的数据库迁移中，更新字段属性时，Doctrine\DBAL\Exception : Unknown database type enum requested, Doctrine\DBAL\Platforms\MySQL57Platform may not support it.

1、Doctrine\DBAL\Exception : Unknown database type enum requested, Doctrine\DBAL\Platforms\MySQL57Platform may not support it.。如图1

图1

PS E:\wwwroot\object> php artisan module:migrate ThemeStoreDB
Migrating: 2022_12_08_173303_alter_theme_store_theme_version_semantic_on_theme_installation_version_preset_table

   Doctrine\DBAL\Exception  : Unknown database type enum requested, Doctrine\DBAL\Platforms\MySQL57Platform may not support it.

  at E:\wwwroot\object\vendor\doctrine\dbal\lib\Doctrine\DBAL\Platforms\AbstractPlatform.php:454
    450|
    451|         $dbType = strtolower($dbType);
    452|
    453|         if (! isset($this->doctrineTypeMapping[$dbType])) {
  > 454|             throw new Exception(
    455|                 'Unknown database type ' . $dbType . ' requested, ' . static::class . ' may not support it.'
    456|             );
    457|         }
    458|

  Exception trace:

  1   Doctrine\DBAL\Platforms\AbstractPlatform::getDoctrineTypeMapping("enum")
      E:\wwwroot\object\vendor\doctrine\dbal\lib\Doctrine\DBAL\Schema\MySqlSchemaManager.php:134

  2   Doctrine\DBAL\Schema\MySqlSchemaManager::_getPortableTableColumnDefinition()
      E:\wwwroot\object\vendor\doctrine\dbal\lib\Doctrine\DBAL\Schema\AbstractSchemaManager.php:820

  Please use the argument -v to see more details.

2、查看迁移文件，更新的字段类型中并不存在 enum

    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::table('theme_installation_version_preset', function (Blueprint $table) {
            $table->string('theme_store_theme_version_semantic', 64)->comment('主题商店的主题版本的语义化')->change();
        });
    }

3、最后确定原因，可能在于此迁移文件所涉及的表中，其他字段的类型为 enum。如图2

图2

4、参考：https://www.shuijingwanwq.com/2022/06/02/6483/ ，使用 DB::statement。执行迁移成功。如图3

图3

    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        $fullTableName = DB::connection()->getTablePrefix() . 'theme_installation_version_preset';
        DB::statement("ALTER TABLE $fullTableName modify theme_store_theme_version_semantic varchar(64) COLLATE utf8mb4_unicode_ci NOT NULL COMMENT '主题商店的主题版本的语义化'");
    }