PHP和MYSQL - 如何显示“已经预订请选择另一个日期”消息[关闭]

Question

I want to display this message "Already booked - please select another date" If two clients select the same product (pg_no)and date (Date). UNIQUE CONSTRAINT

<?php
//connecting string
include("dbconnect.php");

//assigning
$name=$_REQUEST['Name'];
$tele=$_REQUEST['Tele'];
$city=$_REQUEST['City'];

// UNIQUE CONSTRAINT   
$pg_no=$_REQUEST['pg_no']; //product
$date=$_REQUEST['Date'];       //date

//checking if pg_no and Date are same  
$check = mysqli_query($db_connect,"SELECT * FROM lstclient WHERE pg_no='{$pg_no}', Date='{$date}'");

{
    echo "Already booked please select another date<br/>";
}
//if not the insert data
else
{
    $query = mysqli_query($db_connect,"INSERT  INTO  lstclient(pg_no,Name,Tele,City,Date) VALUES('$pg_no','$name','$tele','$city','$date')") or die(mysql_error());
}

// link closing
mysqli_close($db_connect);

// messaging  
if($query)
{
    header("location:index.php?note=failed");
}
else
{
    header("location:index.php?note=success");
}
?>

Answer 1

To view the message on your HTML page, based on the code you have provided, you just need to set a $_GET var:

<?php
if (isset($_GET['note']))
{
    if($_GET['note'] == 'failed';)
    {
        $note = "Those dates have already been booked.";
    }
    else if($_GET['note'] == 'success')
    {
        $note = "You have been booked!";
    }
}
else
{
    $note = "";
}
?>

<div class="message">
    <p class="alert">
        <?php
            if ($note != "")
            {
                echo $note;
            }
        ?>
    </p>
</div>

That would check for a note parameter in your url and set it to $note then output it in your HTML.

You don't need to add anything to the database, you can save the request and log it so you can view which dates are the most popular.