added db insert command to all php files

db.php

 <?php
 
-class db{
-    private $host   = "localhost";
-    private $dbname =  "blood";
-    private $username = "root";
-    private $password = '';
-    protected $con;
-
-    public function __construct(){
-
-        try{
-         // new PDO("msql:host=localhost;dbname=messenger", "root","");   
-
-            $this->con = new PDO("mysql:host=".$this->host. ";dbname=".$this->dbname, $this->username, $this->password );
-           
-            }catch(Exception $e){
-                echo "DataBase Connection Problem: ".$e->getMessage();
-            }
-
-    }
-
-
-}
-
-
-
+$con = mysqli_connect("localhost","root","","blood");
+// Check connection
+if (mysqli_connect_errno())
+  {
+  echo "Failed to connect to MySQL: " . mysqli_connect_error();
+  }
 ?>
\ No newline at end of file

insert.php

 <?php
-$con = mysqli_connect("localhost", "root", "", "blood");
- 
-
-if($con === false){
-    die("ERROR: Could not connect. " . mysqli_connect_error());
-}
+require('db.php');
+$status = "";
 $name = $_POST['name'];
 $blood=$_POST['blood'];
 $age = $_POST['age'];
@@ -16,7 +12,7 @@ $ld= $_POST['ago'];
  
 
 $sql = "INSERT INTO bloo (uname,blood,age,mobile,city,dd) VALUES ('$name', '$blood', $age,'$mobile','$city','$ld')";
-$result=mysqli_query($con,$sql);
+$result=mysqli_query($con,$sql) or die(mysql_error());
 
 if($result==true)
 {