How to change column charset and collation with Doctrine? - doctrine-orm

Question

I'm working on a Symfony 3.4 project and I want for some columns of a table to use charset utf8mb4. The aim behind this is to allow emojis.
Here is an abstract of my Doctrine entity:
/**
* #ORM\Table(name="categories")
*/
class Category {
// ...
/**
* #var string
* #ORM\Column(name="description", type="string", length=255)
*/
private $description;
}
I first updated doctrine configuration:
doctrine:
charset: utf8mb4
Then, I updated the Doctrine configuration of the field category.description:
- * #ORM\Column(name="description", type="string", length=255)
+ * #ORM\Column(name="description", type="string", length=191, options={"charset"="utf8mb4"})
Note that I changed the length from 255 to 191 as utf8mb4 uses 4 bytes instead of 3 for utf8.
Finally, I ran update command:
bin/console doctrine:schema:update --dump-sql
What returned:
ALTER TABLE categories CHANGE description description VARCHAR(191) NOT NULL;
As you can see, there is no update about charset. Moreover, we can see a double whitespace between keywords VARCHAR(191) and NOT, letting suppose there should be something here.
The query I expect would be like this:
ALTER TABLE categories MODIFY `description` VARCHAR(191) COLLATE utf8mb4_unicode_ci NOT NULL;
I then ran the update command:
bin/console doctrine:schema:update --force
But when I re-run the --dump-sql command it returns the same query (with the double whitespaces) over and over.
Even when I manually set the charset of the column to utf8mb4 the query is still the same.
I use v2.6.3 of doctrine/orm.
Did I miss something in my configuration?
Does Doctrine handle column charset?
This does not answer my question as it's about changing collation of all tables. In my case I want to change collation of a single column of a specific table.

Answer 1

Short answer
Doctrine won't do this for you.
Alternative solution
Using DoctrineMigrationBundle allows to create migrations in plain SQL. Thus, you can edit auto-generated migrations to add charset/collation on desired columns.
Generate a new blank migration:
bin/console doctrine:migrations:generate
Then, add the ALTER statement:
use Doctrine\DBAL\Schema\Schema;
use Doctrine\Migrations\AbstractMigration;
final class Version20200113131732 extends AbstractMigration {
public function up(Schema $schema) : void {
$this->addSql('ALTER TABLE categories MODIFY `description` VARCHAR(191) COLLATE utf8mb4_unicode_ci NOT NULL;');
}
public function down(Schema $schema) : void {
$this->addSql('ALTER TABLE categories MODIFY `description` VARCHAR(255) COLLATE utf8_unicode_ci NOT NULL;');
}
}
Finally, just run the migration:
bin/console doctrine:migrations:migrate

Answer 2

It looks like doctrine partialy supports the change of collation on columns (only supported by Drizzle, Mysql, PostgreSQL>=9.1, Sqlite and SQLServer).
See doctrine annotations reference
/**
* #ORM\Table(name="categories")
*/
class Category {
// ...
/**
* #var string
* #ORM\Column(name="description", type="string", length=255, options={"collation"="ascii_general_ci"})
*/
private $description;
}