Ajax和Mysql一键插入2个相同的行
[英]Ajax and Mysql Inserting 2 same row for one click
问题描述
I have a button which has attribute onclick to start javascipt function and my javascript ajax script has xmlhttp object. 
我有一个具有属性onclick的button ，用于启动javascipt函数，而我的javascript ajax脚本具有xmlhttp对象。 It is communicating with dbaction.php 它正在与dbaction.php通信
When I click button everything is okay about script and mysql but the problem is about rows. 当我单击按钮时，关于脚本和mysql的一切都很好，但是问题是关于行的。 It is inserting TWO same row for each click until it rowCount>0 and when after first click echo prints "0" for rowCount() , then if I click again now echo prints "2" for rowCount() It is inserting TWO same row for each click until it rowCount>0并且在第一次单击后，echo为rowCount()打印"0" ，然后如果我再次单击，现在echo为rowCount()打印"2"
Where is the problem? 问题出在哪儿？
<body>
<script type="text/javascript">
function loadName() {
var xmlhttp;
xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function()
{
if (xmlhttp.readyState === 4 && xmlhttp.status === 200)
{
document.getElementById("sample_div").innerHTML = xmlhttp.responseText;
$("#my_button").attr("value", "Sent");
$("#my_button").attr("style", "color:red;");
}
};
xmlhttp.open("GET", "dbaction.php?sender_id=5&receiver_id=6", true);
xmlhttp.send();
}
</script>
<input type="submit" id="buton" onclick="loadName();" value="Submit"/>
<div id="sample_div" style="background-color: khaki; width:50%; margin: 0 auto;">
</div>
</body>
dbaction.php dbaction.php
<?php
//Database connection using PHP PDO(php database objects)
try {
$db = new PDO("mysql:dbname=member;host=localhost", "root", "", array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));
}
catch ( PDOException $e ) {
echo $e->getMessage();
}
$sql= "SELECT * FROM friendship WHERE sender_id=".$_GET["sender_id"]." AND receiver_id=".$_GET["sender_id"]."";
$rs=$db->prepare($sql);
$rs->execute();
$rs->fetch();
$count = $rs->rowCount();
if ($count>0){
echo "You already sent request...";
echo $count;
}
else {
$query = $db->query("INSERT INTO friendship (sender_id, receiver_id, is_approved) VALUES (".$_GET["sender_id"].",".$_GET["receiver_id"].",0)" );
$query->execute();
echo "Request sent";
echo $count;
}
2 个解决方案
解决方案1
1 已采纳 2013-06-25 18:39:08
check the difference :- 检查差异：-
<?php
//Database connection using PHP PDO(php database objects)
try {
$db = new PDO("mysql:dbname=member;host=localhost", "root", "", array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));
}
catch ( PDOException $e ) {
echo $e->getMessage();
}
$sql= "SELECT * FROM friendship WHERE sender_id=".$_GET["sender_id"]." AND receiver_id=".$_GET["sender_id"]."";
$rs=$db->prepare($sql);
$rs->execute();
$rs->fetch();
$count = $rs->rowCount();
if ($count>0){
echo "You already sent request...";
echo $count;
}
else {
$query = $db->query("INSERT INTO friendship (sender_id, receiver_id, is_approved) VALUES (".$_GET["sender_id"].",".$_GET["receiver_id"].",0)" );
//$query->execute();
echo "Request sent";
echo $count;
}
in last else block you are using query() and execute() both,used for execute sql queries one query() directly and execute() for prepared statement 在最后一个else块中，您同时使用query（）和execute（），用于执行sql直接查询一个query（）和execute（）来准备语句
解决方案2
0 2013-06-25 18:49:44
like @dianuj said in his comment, if you saw two requests at the same time in console , then change your js function like below 就像@dianuj在他的评论中说的那样，如果您在console同时看到两个请求，则如下所示更改js function
<script type="text/javascript">
var in_request = false;
function loadName() {
if ( in_request ) {
return false;
}
in_request = true;
var xmlhttp;
xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if ( xmlhttp.readyState === 4 && xmlhttp.status === 200 ) {
in_request = false;
document.getElementById( "sample_div" ).innerHTML = xmlhttp.responseText;
$("#my_button").attr( "value", "Sent" );
$("#my_button").attr( "style", "color:red;" );
}
};
xmlhttp.open( "GET", "dbaction.php?sender_id=5&receiver_id=6", true );
xmlhttp.send();
}
</script>
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