Doctrine\DBAL\Platforms\MySqlPlatform::getDefaultValueDeclarationSQL PHP Method

    public function getDefaultValueDeclarationSQL($field)
    {
        // Unset the default value if the given field definition does not allow default values.
        if ($field['type'] instanceof TextType || $field['type'] instanceof BlobType) {
            $field['default'] = null;
        }
        return parent::getDefaultValueDeclarationSQL($field);
    }