update.php

<?php
session_start();
$userId = $_SESSION["userId"];
require "db_connection.php";
// require "functions.php";
if (isset($_GET["dosageId"])) {

    try {
        $plan_id = $_GET["dosageId"];
        $data = getDosagePlanById($connection, $plan_id);
        echo json_encode($data);

    } catch (Exception $ex) {
        echo json_encode(array("errors" => $ex->getMessage()));
    }

    return;

}

if (isset($_POST["isDosagePlanUpdate"])) {

    if ($_POST["plan_id"] != null && $_POST["isDosagePlanUpdate"] == true) {
        try {

            $plan_id = $_POST["plan_id"];
            $medicine_id = trim($_POST["medicine_id"]);
            $date_taken = trim($_POST["date_taken"]);
            $time_taken = trim($_POST["time_taken"]);

            if (getDosagePlanById($connection, $plan_id) != null) {
                $sql = "UPDATE tbldosageplanner SET medicine_id = :medicine_id, date_taken = :date_taken, time_taken = :time_taken,user_id = :user_id where plan_id = :plan_id";

                if ($stmt = $connection->prepare($sql)) {
                    $stmt->bindParam(":medicine_id", $medicine_id, PDO::PARAM_INT);
                    $stmt->bindParam(":date_taken", $date_taken, PDO::PARAM_STR);
                    $stmt->bindParam(":time_taken", $time_taken, PDO::PARAM_STR);
                    $stmt->bindParam(":plan_id", $plan_id, PDO::PARAM_INT);
                    $stmt->bindParam(":user_id", $user_id, PDO::PARAM_INT);

                    if ($stmt->execute()) {
                        echo json_encode(array("success" => "Dosage Plan Successfully Updated"));
                    } else {
                        echo json_encode(array("error" => "Error Updating Dosage Plan"));

                    }

                } else {
                    echo json_encode(array("error" => "Oops! Something went wrong"));
                }

            } else {

                echo json_encode(array("error" => "Dosage Plan Does not Exist!"));
            }

        } catch (Exception $ex) {
            echo json_encode(array("errors" => $ex->getMessage()));
        }

    }

} else {
    echo json_encode("No Plan ID or User ID");
}

function getDosagePlanById($connection, $dosageId)
{

    try {

        $sql = "SELECT * FROM tbl_dosages WHERE dosageId = :dosageId";
        $stmt = $connection->prepare($sql);
        $stmt->bindParam(":dosageId", $dosageId, PDO::PARAM_INT);
        if ($stmt->execute()) {

            return $stmt->fetch(PDO::FETCH_ASSOC);

        } else {
            return null;
        }

    } catch (Exception $ex) {
        throw $ex;
    } finally {
        $connection = null;
    }

}