We’ve been encountering some errors because of the way we’re querying our database. The following code would work if we were querying for only one line, but doesn’t work in the case of a whole table query!

$schedule=mysqli_query($con,"select * from schedule")or die(mysqli_error($con));
$sched_rows=mysqli_fetch_array($schedule);

print_r($sched_rows);

...we can write it in another way to create an array of rows.

$schedule=mysqli_query($con,"select * from schedule")or die(mysqli_error($con));

$schedule_rows = array();
while($row=mysqli_fetch_array($schedule)){
	$schedule_rows[] = $row;
}

print_r($schedule_rows);

It’s a bit tricky to understand what this code does, but this is the gist of it:

• we query the database;
• we create an empty array that will contain the schedule rows;
• we write a while loop that, each time it runs, will run the mysqli_fetch_array() function to fetch the next row and store it inside the $row variable;
• we push the $row to the $schedule_rows array with the short syntax (using the square brackets);
• we print the schedule rows and we see the whole array.

You wrote something like this in the home.php file at line 75, so check that out!

Additional tip: you can create a new function to do this instead of writing the same code multiple times, like this ⬇️

// you can put this function in a file 
// called fetch_rows.php and include this file 
// each time you want to use this function
$fetch_rows = fn($query) => {
  $rows = array();
  while($row=mysqli_fetch_array($query)) {
    $rows[] = $row;
  }

  return $rows;
}

// let's see it in action
$schedule = mysqli_query($con,"select * from schedule")or die(mysqli_error($con));
$schedule_rows = $fetch_rows($schedule);
print_r($schedule_rows);

Here’s the documentation about mysqli_fetch_array(): https://www.php.net/manual/en/mysqli-result.fetch-array.php.

This procedure creates an array of arrays (the first array is the array of rows, which themselves are arrays). To access properties inside arrays, we need to use the square bracket syntax like this: $row[”time_id”]. What I showed at a certain point during the lesson was actually the syntax to access properties inside objects, which is $row→$row_time_id (this won’t work because we’re working with associative arrays, not objects! Here’s a great Quora thread about the topic: https://www.quora.com/What-is-the-difference-between-an-associative-array-and-an-object-in-PHP). In short, arrays are iterable and consist of key-value pairs, while objects are instances of classes and are not iterable.