mysql_query（）：3不是有效的MySQL-Link资源，无法更新数据：用户''@ localhost'拒绝访问数据库错误[重复]
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>
<?php
$con = mysql_connect("localhost","root","");
if(!$con)
{
die("cannot connect" . mysql_error());
}
mysql_select_db("library",$con);
$sql = "SELECT Renewal_Date FROM ilist ";
$mydata = mysql_query($sql,$con);
$result_array = array();
while($record = mysql_fetch_array($mydata)){
echo"<tr>";
echo "<td>" . $record['Renewal_Date'] . "</td>";
echo "</tr>";
$todayDate = date('m/d/Y');
$date1 = new DateTime($todayDate);
$date2 = new DateTime($record['Renewal_Date']);
if($date2 < $date1)
{
$interval = $date1->diff($date2); // I assume renewal date should be greater , so it must be $date2->diff($date1);
echo "difference " . $interval->y . " years, " . $interval->m." months, ".$interval->d." days ";
echo"<p>";
$extradays=$interval->m;
if($extradays==1)
{
$eday=1;
}else if($extradays==3){
$eday=2;
} else if($extradays==5){
$eday=3;
} else if($extradays==7){
$eday=4;
} else if($extradays==8){
$eday=5;
} else if($extradays==10){
$eday=6;
} else if($extradays==12){
$eday=7;
}
else{
$eday=0;
}
$yd= $interval->y*365*3+$interval->d*3;
$ydm=$yd+$interval->m*30*3;
$ydm=$ydm+($eday*3);
}
else
{
$ydm=0;
}
$sql = 'UPDATE ilist
SET Fine="$ydm"';
mysql_select_db('library');
$retval = mysql_query($sql,$con);
if(! $retval )
{
die('Could not update data: ' . mysql_error());
}
echo "Updated data successfully
";
mysql_close($con);//("UPDATE ilist SET Fine=$ydm");
}
?>
<body>
</body>
</html>
two errors are occuring when i compile 1)mysql_query(): 3 is not a valid MySQL-Link resource 2)Could not update data: Access denied for user ''@'localhost' to database error
All i want do is to update database in which I newly added a column called Fine . the entire fine column is zero initially, the rest of the columns in ilist table are filled earlier from php and html form. Do I need to add a textbox for fine also in form? but i am not going to enter anything from form into fine textbox.
</div>
when i compile
PHP is interpreted
Could not update data: Access denied for user ''@'localhost' to database error
Self-explanatory. Invalid MySQL details. Check those with the MySQL Config
