Can someone explain the principle behind this simple code please? - php

Question

Im having difficulty comprehending a line of code that i am using to retrieve results from a mysql database.
I connect to the database with
<?php
try
{
$pdo = new PDO('mysql:host=localhost;dbname=****', '****',
'****');
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$pdo->exec('SET NAMES "utf8"');
}
catch (PDOException $e)
{
$error = 'Unable to connect to the database server.' . $e->getMessage;
echo $error;
exit();
}
this is fine. the connection works.
to retrive the results i use this code....
$sql = 'SELECT joketext FROM joke';
$results = $pdo->query($sql);
this also is fine but then i use a foreach loop to loop through the result set as so...
foreach ($results as $result){
$jokes[] = $result['joketext'];
}
and then another foreach to loop through $jokes as so...
foreach ($jokes as $joke) {
echo $joke;
}
now this all works it displays the joketext i wanted from the mysql table. However i dont understand the line...
$jokes[] = $result['joketext'];
does this means I am assigning the result set to an array? what does $jokes[]= mean? and why do i have to do this?
I thought i was retrieving strings of text from the database table. The table has an id, joketext, jokedate, and authorid as columns. But if im only selecting the joketext column surely that retrieves a list of all the joketext entries and therefore i can just loop through with a foreach echoing out the results?

Answer 1

The $jokes[] syntax is appending the joke text string to the $jokes array. If the array doesn't exist, it will be created.
It's the same as doing:
array_push($jokes, $result['joketext']);
If you don't need to create a new array, you can just work with the joke text directly in the $results foreach, if you prefer.

Answer 2

your query only selects for one column joketext so you don't have any of the other column data in your result set.
Using $jokes[] = .. is a shorthand way of assigning a value to a new element in the $jokes array. You don't necessarily need to do this. It is just commonly done so that you can use the data later on, in multiple places if you want. Alternatively, you can just work with the result set directly each time. That isn't as commonly done though since the result set is an object or resource that contains more than what you may actually need. But if you're just looking to output the joketext immediately, then you can skip putting it into a separate array and just echo $result['joketext']; in your first loop

Answer 3

$jokes[] = appends a new value to an array and is the same as doing $jokes[count($jokes)] (not completely correct but is a simple way of explaining it).
Technically, you don't have to put all the values in a new array, you could use the original loop instead.
array_push has the same functionality, you can read up about it here

Answer 4

If I understand you correctly then I believe you are correct. The second foreach is not needed, you can simply echo the $result['joketext'] during the first foreach and skip the second one altogether.
so delete the second foreach and edit the first one as follows:
foreach ($results as $result){
echo( $result['joketext'] );
}