Question

I have a small form that is generated from a mysqli->query and I’ve set each inputs name to be an array, such as name="Shift_ID[]". Then I have a for loop that is meant to UPDATE the records one at a time as it loops through. The problem I have is that the $i variable is a different value within the same loop and I don’t understand why. This is my code:

if(isset($_POST['update_submit']))
{
    $id = $_POST['Shift_ID'];
    $name = $_POST['Shift_Name'];
    $short_name = $_POST['Shift_Short_Name'];
    $color  = $_POST['Shift_Color'];
    $shift_total_records = "5";

    for($i = 0; $i <= $shift_total_records; $i++) 
    {
        $sql = ("UPDATE shift SET Shift_ID = '$id[$i]', Shift_Name = '$name[$i]', Shift_Short_Name = '$short_name[$i]', Shift_Color = '$color[$i]' WHERE Shift_ID = '$i'");

        echo "SQL: " . $sql . "<br>";

        if(!$result_shift_update = $mysqli->query($sql))
        {
            die ('There was an error updating the shift table [' . $mysqli->error . ']');
        }
    }
}

The echo returns this:

SQL: UPDATE shift SET Shift_ID = '1', Shift_Name = 'Morning', Shift_Short_Name = 'AM', Shift_Color = '#FF0000' WHERE Shift_ID = '0'

I was expecting Shift_ID = '1' and WHERE Shift_ID = '1'. Can someone explain why this is happening? Also, before someone says it, I do know this is open to injection attacks and I need to use prepared statements.

*EDIT: * The reason I had it Shift_ID = '$id[$i]' and WHERE Shift_ID = '$i' was because I wanted to user to be able to change the Shift_ID field if they wanted to. The point would be to have the option to rearrange the order. The Shift_ID is the PRIMARY KEY, so they would get an error if they tried to use the same number twice, but is there a way to make this do what I want?

Answer 1

You’ve used a different variable in each location. Do you mean this:

$sql = ("UPDATE shift SET Shift_ID = '$id[$i]', Shift_Name = '$name[$i]', Shift_Short_Name = '$short_name[$i]', Shift_Color = '$color[$i]' WHERE Shift_ID = '$id[$i]'");