docencia.php

<?php
if(isset($_POST['tipo']) && !empty($_POST['tipo'])) {
    $tipo = $_POST['tipo'];
    switch($tipo) {
        case 'get' : getDocenciaList();break;
        case 'insert' : insertDocencia($_POST['emp_cod']);break;// do something;break;
        // other cases
    }
}

function getDocenciaList(){
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "sap2000";

$conn = mysqli_connect($servername, $username, $password, $dbname);
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
$rows = array();
$sql = "SELECT * FROM docencia";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
    while($r = mysqli_fetch_assoc($result)) {
    $rows[] = $r;
}
print json_encode($rows);
} else {
    echo "0 results";
}
mysqli_close($conn);
}

function insertDocencia($emp_cod){
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "sap2000";

$conn = mysqli_connect($servername, $username, $password, $dbname);
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

$sql = "INSERT INTO docencia (emp_cod)
VALUES ('$emp_cod')";

if ($conn->query($sql) === TRUE) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}
mysqli_close($conn);
}
?>