Laravel数据迁移

Question

是否有办法在Laravel中进行数据迁移？我已经找到了一些关于如何为数据库添加种子的说明，但它没有涵盖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。

一个可能的解决方案是查询数据库并更新循环中的每个记录。这种方法的问题是，在迁移(Django为此提供了一个解决方案。)期间，模型可能不会反映表模式。

Answer 1

Laravel的迁移内置于:) http://laravel.com/docs/migrations

简单地跑

php artisan make:migration migration_name_here

它将在app/数据库/迁移下创建一个迁移。然后，您可以在up()和down()方法中使用Laravel的数据库类。

以这个为例..。

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');
        });
    }
}