在php中调试的问题

Question

我正在运行一个php脚本，它有一个while循环和文件写入，这使得它需要一些time.The问题，当它似乎没有打印错误在运行时，它打印他们在脚本完全执行后，有时错误是在循环中，所以它重复每一次循环和它花费了我很多时间。

下面是示例code

<!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="Algorithm" content="text/html; charset=utf-8" />
<title>Delta Compression</title>
</head>
<body>

<?php
//DB Connection
$dbuser = "root";
$dbpass = "";
$dbname = "delta_compression";
$dbhost = "localhost";

//Database Connection
$con = mysql_connect($dbhost,$dbuser,$dbpass);
if (!$con)
{
die('Could not connect: ' . mysql_error());
}

mysql_select_db($dbname, $con);
echo "Database Connected !";

//Variable declaration 
$file="flag_track.txt";
$result=mysql_query("select * from d_5");
$total_rows=mysql_num_rows($result);
$limit=256;

while($i < $total_rows){
    //increasing time limit 
    set_time_limit(0);
    //getting the value from the row of reading
    $reading=mysql_result($result,$i,'reading');
    //if first flag is set 
        if(!(firstFlag())) {
            delta();
            }
    //convert the decimal to binary and store in db 
    if(saveDelta(decbin($diffrence))== flase){
        echo"Error saving the data in DB";

        }   

}
function delta(){

        $delta=$flag-$reading;
        file_put_contents ($file, $flag."<br>".$delta, FILE_APPEND)."<br>";             
        if( $delta > $limit){
                $flag=$reading;
                file_put_contents ($file, $flag."<br/>".$delta,     FILE_APPEND)."<br>";

                }
}

function firstFlag(){
if($flag == null){
        //set the flag
        $flag=$reading;
        //saving the flag 
        file_put_contents ($file, $flag, FILE_APPEND)."<br>";
        return true;
        }
        else {

return false;
}
}


function saveDelta($dif) {

if(mysql_query("INSERT INTO e_x_1 (delta_of_reading) VALUES ('b" . $dif . "')")){
return true; //on success
} else {
return false; //on failure
}

}
?>

</body>
</html>

Answer 1

错误在以下语句中

mysql_query("INSERT INTO e_x_1 (delta_of_reading) VALUES (b'$dif')");

它应该是这样的：

mysql_query("INSERT INTO e_x_1 (delta_of_reading) VALUES ('b" . $dif . "')"); 
//i don't know if you want `b` there or it is an error

由于在while循环中调用了函数saveDelta($dif)，因此它将多次打印错误。您可以返回错误代码并检查查询是否成功执行。

function saveDelta($dif) {

  if(   mysql_query("INSERT INTO e_x_1 (delta_of_reading) VALUES ('b" . $dif . "')") ){
    return true; //on success
  } else {
    return false; //on failure
  }

}

在while循环中，检查如下：

if( saveDelta(decbin($diffrence) === false ){
  //print error and return or do whatever you like to do
}