Laravel 数据迁移

php laravel

2022-08-30 18:21:06

有没有办法在Laravel中进行数据迁移？我找到了一些关于如何为数据库设定种子的说明，但它没有涵盖我需要将一个字段拆分为多个字段或将多个字段合并为一个字段的情况。

一种可能的解决方案是查询数据库并在循环中更新每条记录。这种方法的问题在于，模型在迁移过程中可能无法反映表模式（Django为此提供了解决方案）。

答案 1

Laravel内置了迁移:)http://laravel.com/docs/migrations

轻松运行

php artisan make:migration migration_name_here

它将在应用程序/数据库/迁移下创建迁移。然后，您可以在up（）和down（）方法中使用Laravel的数据库类。

让我们以此为例...

class SplitColumn extends Migration {

    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::table('table_name', function($table)
        {
            // Create new columns for table_name (1 column split into 2).
            $table->string('new_column');
            $table->string('new_column_b');
        });

        // Get records from old column.
        $results = DB::table('table_name')->select('old_column')->get();

        // Loop through the results of the old column, split the values.
        // For example, let's say you have to explode a |.
        foreach($results as $result)
        {
            $split_value = explode("|", $result->old_column);

            // Insert the split values into new columns.
            DB::table('table_name')->insert([
                "new_column"    =>  $split_value[0],
                "new_column_b"  =>  $split_value[1]
            ]);
        }

        // Delete old column.
        Schema::table('table_name', function($table)
        {
            $table->dropColumn('old_column');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::table('table_name', function($table)
        {
            // Re-create the old column.
            $table->string('old_column');
        });

        // Get records from old column.
        $results = DB::table('table_name')->select('new_column', 'new_column_b')->get();

        // Loop through the results of the new columns and merge them.
        foreach($results as $result)
        {
            $merged_value = implode("|", [$result->new_column, $result->new_column_b]);

            // Insert the split values into re-made old column.
            DB::table('table_name')->insert([
                "old_column"    =>  $merged_value
            ]);
        }

        // Delete new columns.
        Schema::table('table_name', function($table)
        {
            $table->dropColumn('new_column');
            $table->dropColumn('new_column_b');
        });
    }
}

答案 2