diff --git a/app/Controllers/PatVisit.php b/app/Controllers/PatVisit.php
index 488661d..3c1ecf6 100644
--- a/app/Controllers/PatVisit.php
+++ b/app/Controllers/PatVisit.php
@@ -13,18 +13,19 @@ class PatVisit extends Controller {
 		$this->visnum_prefix = "DV";
 	}
 
-	private function preparePVID($PVID) {
+	private function preparePVID() {
 		$row = $this->db->table('counter')->select('*')->where('CounterID','2')->get()->getResultArray();	
 		$cValue = $row[0]['CounterValue'];
 		$cStart = $row[0]['CounterStart'];
 		$cEnd = $row[0]['CounterEnd'];
 		$cReset = $row[0]['CounterReset'];
-		$cPad = strlen((string)$cEnd);	
-		$cValue_next = $cValue++;
+		$cPad = strlen((string)$cEnd);
+		if($cValue > $cEnd) { $cValue = $cStart; }
+		$cnum = $this->visnum_prefix.str_pad($cValue, $cPad, "0", STR_PAD_LEFT); 
+		$cValue_next = $cValue+1;
 		// next value > end, back to start
-		if($cValue_next > $cEnd) { $cValue_next = $cStart; }
-		$row = $this->db->table('counter')->set('CounterValue', $cValue_next)->where('CounterID','2');
-		return $this->visnum_prefix.str_pad($cValue, $cPad, "0", STR_PAD_LEFT);
+		$this->db->table('counter')->set('CounterValue', $cValue_next)->where('CounterID','2')->update();
+		return $cnum;
 	}
 	
 	public function show($PVID = null) {
@@ -103,7 +104,10 @@ class PatVisit extends Controller {
 			$input = $this->request->getJSON(true);
 			if (!$input) { return $this->respond(['status' => 'error', 'message' => 'Invalid JSON input'], 400); }
 			
-			$input['PVID'] = $this->preparePVID($input['PVID']);
+			if($input['PVID'] =='' || !isset($input['PVID'])) {
+				$input['PVID'] = $this->preparePVID();
+			}
+			
 			$dataPatVisit = $this->preparePatVisitData($input);
 			$dataPatDiag = $this->preparePatDiagData($input);
 			$dataPatVisitAdt = $this->preparePatVisitAdtData($input);
@@ -140,7 +144,6 @@ class PatVisit extends Controller {
 				'message' => 'Data insert success',
 				'data'    => $dataPatVisit
 			], 201);
-
 		} catch (\Exception $e) {
 			$this->db->transRollback();
 			return $this->failServerError('Something went wrong: ' . $e->getMessage());
diff --git a/app/Database/Migrations/2025-09-09-155526_Pat_Visit.php b/app/Database/Migrations/2025-09-09-155526_Pat_Visit.php
index 4ae0d88..2794ce5 100644
--- a/app/Database/Migrations/2025-09-09-155526_Pat_Visit.php
+++ b/app/Database/Migrations/2025-09-09-155526_Pat_Visit.php
@@ -19,6 +19,7 @@ class CreatePVTables extends Migration {
     ]);
     $this->forge->addField('CreateDate DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP');
     $this->forge->addKey('InternalPVID', true);
+    $this->forge->addUniqueKey('PVID', true);
     $this->forge->createTable('patvisit');
 
     // patdiag