private function _getTableColumns($tableName)
{
$schema = Db::getInstance()->query("SHOW COLUMNS FROM {$tableName}")->fetchAll();
$tableColumns = array();
foreach ($schema as $columnInfo) {
$columnName = $columnInfo['Field'];
$columnDefault = $columnInfo['Default'];
$columnType = $this->dataTypeToPhpType($columnInfo['Type']);
$tableColumns[$columnName] = new DatabaseColumn($columnName, $columnType, $columnDefault);
}
return $tableColumns;
}