php mysql插入唯一值

Question

定义port为随机五位数，然后向表中插入数据，其中port是唯一值， 由于表中已经存在大量记录，提交后经常出现重复的错误提示，如何解决

$port=rand(10000,54999);

$con = mysqli_connect("sever","user","passwd");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}

mysqli_query($con,"INSERT INTO dbdb.list (port, wechat) VALUES ( '".$port."', 'wechat') or die(mysqli_error($con));

mysqli_close($con);

Answer 1

<?php
$con = mysqli_connect("sever","user","passwd");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}

function create_code(){//生成唯一5位数
    global $con;
    mt_srand((double)microtime() * 1000000);//用 seed 来给随机数发生器播种。
    $port=mt_rand(10000,54999);
    $query =mysqli_query($con,"select * from dbdb.list where port='".$port."'");
    $rt =mysqli_fetch_array($query,MYSQLI_ASSOC); 
    if($rt){//判断随机数是否存在，存在就重新生成，直到不存在为止
        $port=create_code();
    }
    return $port;
}
$port=create_code();
mysqli_query($con,"INSERT INTO dbdb.list (port, wechat) VALUES ( '".$port."', 'wechat')") or die(mysqli_error($con));
mysqli_close($con);
?>

简单的一个例子