PHP prepared statement insert from a loop of data

Question

Any ideas as to why my data isn't being updated? Is their something fundamentally wrong with how I'm writing my prepared statement?

The form:

while($log_dates = mysqli_fetch_assoc($q_log_dates_result)) {   
 echo "<tr>";
 echo "<input type='hidden' name='data[][log_dates_ID]' value='" . $log_dates['log_dates_ID'] . "'/>";
 echo "<td><input type='text' name='data[][week_date]' value='" . $log_dates['week_date'] . "' /></td>";
 echo "<td><input type='text' name='data[][crew_chief]' value='" . $log_dates['crew_chief'] . "' readonly /></td>";
 echo "<td><input type='text' name='data[][monday_crew]' value='". $log_dates["monday_crew"] ."'/></td>";
 echo "</tr>";
} // end while loop

PHP:

if (isset($_POST['submit'])) {

$stmt = $connection->stmt_init();
if($stmt->prepare("UPDATE log_dates SET (week_date, crew_chief, monday_crew) VALUES (?, ?, ?) WHERE log_dates_ID = ?")) {

// Bind your variables to replace the ?s
$stmt->bind_param('sssi', $week_date, $crew_chief, $monday_crew, $log_dates_ID);


$returnedData = $_POST['data'];



for($i=0;$i<count($returnedData);$i+=4){
    $log_dates_ID = $returnedData[$i]['log_dates_ID'];
    $week_date = $returnedData[$i+1]['week_date'];
    $crew_chief = $returnedData[$i+2]['crew_chief'];
    $monday_crew = $returnedData[$i+3]['monday_crew'];
    $stmt->execute();
}


    // Close statement object
    $stmt->close();
}


}

Answer 1

Your UPDATE syntax is not correct. It should be:

UPDATE log_dates
SET week_date = ?, crew_chief = ?, monday_crew = ?
WHERE log_dates_ID = ?

You're trying to user INSERT syntax in an UPDATE statement. They're not similar at all.

Documentation

Answer 2

I would do it like this...

Inside a function...

function updatedata($week_date, $crew_chief, $monday_crew, $log_dates_ID){
 $stmt = $connection->stmt_init();
 $stmt->prepare("UPDATE log_dates SET (week_date, crew_chief, monday_crew) VALUES (?, ?, ?) WHERE log_dates_ID = ?")) 
 $stmt->bind_param($week_date, $crew_chief, $monday_crew, $log_dates_ID);
 $stmt->execute();
}

Then in your loop...

for($i=0;$i<count($returnedData);$i+=4){
$log_dates_ID = $returnedData['log_dates_ID'][$i];
$week_date = $returnedData['week_date'][$i];
$crew_chief = $returnedData['crew_chief'][$i];
$monday_crew = $returnedData['monday_crew'][$i];
updatedata($week_date, $crew_chief,$monday_crew, $log_dates_ID);
}