diff --git a/Script.php b/Script.php
index f664eee..eecb7cd 100644
--- a/Script.php
+++ b/Script.php
@@ -913,18 +913,32 @@ if (!empty($_GET["ignoreremarking"])) {
 #Assign TA
 
 if (!empty($_GET["assignTA"])) {
-
     $id = mysqli_real_escape_string($con, $_GET["id"]);
     $ta = mysqli_real_escape_string($con, $_GET["ta"]);
 
-    $sql = "INSERT INTO `course_ta`(`Course_ID`, `TA`) VALUES ('$id','$ta')";
+    // Check if the TA is already assigned to the course
+    $check_sql = "SELECT * FROM `course_ta` WHERE `Course_ID`='$id' AND `TA`='$ta'";
+    $check_result = $con->query($check_sql);
 
-    if ($con->query($sql) === TRUE) {
-
-        $_SESSION["info_Admin_Courses"] = $type . " Course TA Assigned ";
-        header("Location: Admin.php");
+    if ($check_result->num_rows > 0) {
+        // Alert user about the duplicate assignment
+        echo "<script>
+            alert('The selected TA is already assigned to this course.');
+            window.location.href='Admin.php';
+        </script>";
     } else {
-        echo "Error: " . $sql . "<br>" . $con->error;
+        // Proceed with the TA assignment
+        $sql = "INSERT INTO `course_ta`(`Course_ID`, `TA`) VALUES ('$id','$ta')";
+
+        if ($con->query($sql) === TRUE) {
+            $_SESSION["info_Admin_Courses"] = $type . " Course TA Assigned ";
+            header("Location: Admin.php");
+        } else {
+            echo "<script>
+                alert('You must select a TA first!.');
+                window.location.href='Admin.php';
+            </script>";
+        }
     }
 }