为什么这个 mysqli 准备好的插入语句不能处理多个值？

Question

I am having issues using a prepared insert statement. The script is supposed to read the contents of the.txt file and insert the data into the corresponding columns in my database. Here is the error I keep getting when trying to insert.

Fatal error: Uncaught mysqli_sql_exception: Column 'propertyName' cannot be null in C:\xamppp\htdocs\php7\propertyUpload.php:19 Stack trace: #0 C:\xamppp\htdocs\php7\propertyUpload.php(19): mysqli_stmt_execute(Object(mysqli_stmt)) #1 {main} thrown in C:\xamppp\htdocs\php7\propertyUpload.php on line 19

BTW: The contents of the.txt are in an array like so:

TEST1000, PROPERTY1
TEST2000, PROPERTY2
TEST3000, PROPERTY3

<?php
    include 'config.php';
    if (empty($_SERVER['HTTP_REFERER']))
    {
        header('Location: ""');
        exit;
    }
    ini_set("auto_detect_line_endings", true);
    $open = fopen('test22-7-18.txt','r');
    while (!feof($open))
    {
        $getTextLine = fgets($open);
        $explodeLine = explode(",",$getTextLine);
        list($accountCode,$propertyName) = $explodeLine;
        $sql = "INSERT INTO properties (accountCode, propertyName) values(?, ?)";
        if ($stmt = mysqli_prepare($link, $sql))
        {
            mysqli_stmt_bind_param($stmt,"ss",$accountCode, $propertyName);
            (mysqli_stmt_execute($stmt));
        }
    }
    fclose($open);
    
     ?>

However, when I change my code to this the contents are inserted correctly:

<?php
include 'config.php';
if (empty($_SERVER['HTTP_REFERER']))
{
    header('Location: ""');
    exit;
}
ini_set("auto_detect_line_endings", true);
$open = fopen('test22-7-18.txt','r');
while (!feof($open))
{
    $getTextLine = fgets($open);
    $explodeLine = explode(",",$getTextLine);
    list($accountCode,$propertyName) = $explodeLine;
    $sql = "INSERT INTO properties (accountCode, propertyName) values(? , '$propertyName')";
    if ($stmt = mysqli_prepare($link, $sql))
    {
        mysqli_stmt_bind_param($stmt,"s",$accountCode);
        (mysqli_stmt_execute($stmt));
    }
}
fclose($open);
?>

Is the second script open to SQL injection, if not could I leave it as is? Does anyone know why I can't get the first statement to work?

Answer 1

The value of $propertyName is null , but the propertyName column in the table is declared NOT NULL .

This is most likely due to your incorrect use of while( feof($open)) , which causes you to call fgets() an extra time at the end of the file. This sets $getTextLine to false , and explode() returns [""] , so $bar is set to null (there's probably also an "Undefined offset" warning that you're not printing).

When you use string substitution null expands to an empty string, so you're inserting an empty string in that row. This prevents the error, but you're probably not getting the desired result, since it inserts an extra row with empty values.

Use

while ($getTextLine = fgets())

as your looping criteria instead of while ( feof($getTextLine))