How to Alter Blob to Varchar in Laravel Make:Migration - mysql

Question

I need to change a Blob field type to a Varchar(128). The data in the field will fit the target field size, it's text, and shouldn't have a problem with UTF-8.
Sample data, all data is in this format:
{"weight":"0","height":"0","width":"0","length":"0"}
I'm using Laravel Make:migrate to handle the conversion.
How should I write the SQL?
I know how to write a Laravel Migration. I also know how to alter a field. But a Blob isn't a text field nor is a Blob normally converted down to a Varchar. I've done some manual UTF-8 conversion of Blobs in the past and know you can mess up your data if you don't do it right. So my concern here is to not mess up my data with a Laravel Migrate. I don't believe the migrate 'down' method can undo corrupted data.
If my data fits the varchar target size and if the data fits the UTF-8 charset, am I good with a straight forward Alter statement:
DB::query("ALTER TABLE DB1.products CHANGE COLUMN dimensions dimensions varchar(128) DEFAULT NULL;");

Answer 1

You shouldn't use sql for this, just create a migration and use change method
Schema::table('table_name', function ($table) {
$table->string('column_name')->change();
});
https://laravel.com/docs/5.7/migrations#modifying-columns
Considering your comment sql would be
ALTER TABLE tablename MODIFY column_name VARCHAR(128);

Answer 2

Run composer install and then composer update in the console and
drop your table from the database and also delete the migration ,then create a new migration using
php artisan make:migration change_col_datatype --table=table_name
and then make changes as below
Schema::table('your_table_name', function ($table) {
$table->string('your_table_name');
});
public function down()
{
Schema::dropIfExists('tablename');
}

Answer 3

The SQL statment:
\DB::statement('ALTER TABLE products CHANGE COLUMN dimensions dimensions VARCHAR(128) DEFAULT NULL;');
Worked fine.