I solved it like this:
Insert these lines into getDdlTypeByColumnType function of "vendor/magento/module-eav/Model/ResourceModel/Helper.php"
case 'int unsigned':
$columnType = 'int';
break;
case 'smallint unsigned':
$columnType = 'smallint';
break;
BEFORE:
public function getDdlTypeByColumnType($columnType)
{
switch ($columnType) {
case 'char':
case 'varchar':
$columnType = 'text';
break;
case 'tinyint':
$columnType = 'smallint';
break;
default:
break;
}
return array_search($columnType, $this->_ddlColumnTypes);
}
AFTER:
public function getDdlTypeByColumnType($columnType)
{
switch ($columnType) {
case 'int unsigned':
$columnType = 'int';
break;
case 'smallint unsigned':
$columnType = 'smallint';
break;
case 'char':
case 'varchar':
$columnType = 'text';
break;
case 'tinyint':
$columnType = 'smallint';
break;
default:
break;
}
return array_search($columnType, $this->_ddlColumnTypes);
}