PHP正则表达式和CSV验证

我正在尝试创建一个CSV检查器，它将检查的数据插入数据库，并将任何不成功的数据添加到.txt文件中。我正试图使用正则表达式来验证我插入的数据，没有任何验证的while循环可以正常工作并插入，但一旦使用正则表达式，它就不起作用。

<?php
    include_once('connection.php');
    error_reporting(E_ALL);
    date_default_timezone_set('Europe/London');
    $date = date('d/m/y h:i:s a', time());
    $filetxt = "./errors.txt";
    $errors = array();
    $var1 = 5;
    $var2 = 1000;
    $var3 = 10;
    $sql = '';
    if(isset($_POST["Import"]))
    {
        echo $filename=$_FILES["file"]["tmp_name"]; 
        if($_FILES["file"]["size"] > 0)
        {
            $file = fopen($filename, "r");
            while(($emapData = fgetcsv($file, 10000, ",")) !==FALSE)
            {
                if(isset($_GET['strProductCode']))
                {
                    $emapData[0] =  $conn->real_escape_string(trim($_POST['strProductCode']));
                    if (!preg_match("^[a-zA-Z0-9]+$^", $_POST['strProductCode']))
                    {
                        $errors['strProductCode'];
                    }
                }
                if(isset($_GET['strProductName']))
                {
                    $emapData[1] =  $conn->real_escape_string(trim($_GET['strProductName']));
                    if (!preg_match("^[a-zA-Z0-9]+$^", $_POST['strProductName']))
                    {
                        $errors['strProductName'];
                    }
                }
                if(isset($_GET['strProductDesc']))
                {
                    $emapData[2] =  $conn->real_escape_string(trim($_GET['strProductDesc']));
                    if (!preg_match("^[a-zA-Z0-9]+$^", $_POST['strProductDesc']))
                    {
                        $errors['strProductDesc'];
                    }
                }
                if(isset($_GET['intStock']))
                {           
                    if (!preg_match("^[0-9]", $_POST['intStock']))
                    {
                        $errors['intStock'];
                    }
                }
                if(isset($_GET['intPrice']))
                {
                    if (!preg_match("[0-9]", $_POST['intPrice']))
                    {
                        $errors['intPrice'];
                    }
                }
                if(isset($_GET['dtmDiscontinued'])){
                    if($emapData[6] == preg_match("[a-zA-Z]", $_POST['dtmDiscontinued']))
                    {
                        $emapData[6] = $date;
                        echo $date;
                    }else{
                            $emapData[6] = Null;
                        }
                }
                if(count($errors > 0))
                {
                    // errors 
                    $write = "$emapData[0], $emapData[1], $emapData[2], $emapData[3], $emapData[4], $emapData[5], $emapData[6]'r'n";     
                    file_put_contents($filetxt , $write , FILE_APPEND);
                }else{
                    // insert into Database
                        $sql = "INSERT INTO tblproductdata(strProductCode, strProductName, strProductDesc, intStock, intPrice, dtmAdded, dtmDiscontinued) VALUES('$emapData[0]','$emapData[1]','$emapData[2]','$emapData[3]','$emapData[4]','$date','$emapData[6]')";
                    $res=$conn->query($sql);
                    }
            }
            fclose($file);
            echo "CSV File has successfully been Imported";
            echo "<br>";
            echo "Any errors within the CVS Database are reported here.";
            echo "<br>";
            $fh = fopen($filetxt, 'r');
            $theData = fread($fh, filesize($filetxt));
            fclose($fh);
            echo $theData;
        }else{
            echo "Invalid File: Please Upload a Valid CSV File";    
        }
            header("Location: index.php");
    }
?>

我的PHP知识不是很好，但这是我最好的尝试。如有任何帮助，我们将不胜感激。