[HttpFoundation] fixed PDO session handler for Oracle (closes #5829)

src/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php

@@ -168,7 +168,9 @@ public function write($id, $data)
         $encoded = base64_encode($data);
 
         try {
-            if ('mysql' === $this->pdo->getAttribute(\PDO::ATTR_DRIVER_NAME)) {
+            $driver = $this->pdo->getAttribute(\PDO::ATTR_DRIVER_NAME);
+
+            if ('mysql' === $driver) {
                 // MySQL would report $stmt->rowCount() = 0 on UPDATE when the data is left unchanged
                 // it could result in calling createNewSession() whereas the session already exists in
                 // the DB which would fail as the id is unique
@@ -180,6 +182,14 @@ public function write($id, $data)
                 $stmt->bindParam(':data', $encoded, \PDO::PARAM_STR);
                 $stmt->bindValue(':time', time(), \PDO::PARAM_INT);
                 $stmt->execute();
+            } elseif ('oci' === $driver) {
+                $stmt = $this->pdo->prepare("MERGE INTO $dbTable USING DUAL ON($dbIdCol = :id) ".
+                       "WHEN NOT MATCHED THEN INSERT ($dbIdCol, $dbDataCol, $dbTimeCol) VALUES (:id, :data, sysdate) " .
+                       "WHEN MATCHED THEN UPDATE SET $dbDataCol = :data WHERE $dbIdCol = :id");
+
+                $stmt->bindParam(':id', $id, \PDO::PARAM_STR);
+                $stmt->bindParam(':data', $encoded, \PDO::PARAM_STR);
+                $stmt->execute();
             } else {
                 $stmt = $this->pdo->prepare("UPDATE $dbTable SET $dbDataCol = :data, $dbTimeCol = :time WHERE $dbIdCol = :id");
                 $stmt->bindParam(':id', $id, \PDO::PARAM_STR);