How to access a variable inside a function from a different file? - php

Question

I have two files, a functions.php which contains a PDO object to connect to a database and contains columns as variables and a index.php to output the variable containing the data. the database connection works however when I try to echo a variable from my function it is returned undefined, What am i doing wrong;
functions.php
<? php
function connectDB() {
$hostname = 'xxxxxxxx';
$db = 'xxxxxxx';
$user = 'xxxxxxxx';
$pass = 'xxxxxxx';
$dbh = new PDO("mysql:host=$hostname; dbname=$db; charset=utf8", $user, $pass, array(PDO::ATTR_EMULATE_PREPARES => false, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
$sql = "//my query";
$query = $dbh->prepare($sql);
$query->execute(array('//value','//value'));
$query->setFetchMode(PDO::FETCH_ASSOC);
while ($r = $query->fetch()):
$var1 = $r['column1'];
$var2 = $r['column2'];
$var3 = $r['column3'];
$var4 = $r['column4'];
$var5 = $r['column5'];
endwhile;
}
?>
index.php
<?php
include 'functions.php';
?>
<?php
try {
connectDB();
echo 'You are connected to Database';
echo $var1;
$dbh = null;
}
catch(PDOException $e) {
echo $e -> getMessage();
}
?>

Answer 1

those variables are by default local to your connectDB() function, so you will have to either declare them in global scope beforehand, or use the $GLOBALS to set them:
Method 1
<? php
$var1 = '';
$var2 = '';
$var3 = '';
$var4 = '';
$var5 = '';
function connectDB() {
$hostname = 'xxxxxxxx';
$db = 'xxxxxxx';
$user = 'xxxxxxxx';
$pass = 'xxxxxxx';
$dbh = new PDO("mysql:host=$hostname; dbname=$db; charset=utf8", $user, $pass, array(PDO::ATTR_EMULATE_PREPARES => false, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
$sql = "//my query";
$query = $dbh->prepare($sql);
$query->execute(array('//value','//value'));
$query->setFetchMode(PDO::FETCH_ASSOC);
while ($r = $query->fetch()):
$var1 = $r['column1'];
$var2 = $r['column2'];
$var3 = $r['column3'];
$var4 = $r['column4'];
$var5 = $r['column5'];
endwhile;
}
?>
Method 2
<? php
function connectDB() {
$hostname = 'xxxxxxxx';
$db = 'xxxxxxx';
$user = 'xxxxxxxx';
$pass = 'xxxxxxx';
$dbh = new PDO("mysql:host=$hostname; dbname=$db; charset=utf8", $user, $pass, array(PDO::ATTR_EMULATE_PREPARES => false, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
$sql = "//my query";
$query = $dbh->prepare($sql);
$query->execute(array('//value','//value'));
$query->setFetchMode(PDO::FETCH_ASSOC);
while ($r = $query->fetch()):
$GLOBALS['var1'] = $r['column1'];
$GLOBALS['var2'] = $r['column2'];
$GLOBALS['var3'] = $r['column3'];
$GLOBALS['var4'] = $r['column4'];
$GLOBALS['var5'] = $r['column5'];
endwhile;
}
?>
Sincerely, your copy-paste-service :)

Answer 2

you can generally access variables in one of two ways, either as a parameter passed to the function or by declaring, within the function, the variable as global. Hope the following helps a little
function banana( $externalvar=false ){
echo $externalvar;
}
or
function banana(){
global $externalvar;
echo $externalvar;
}

Answer 3

The smart code should use yield keyword:
function connectDB() {
// ...
$output = [];
$index = 0;
while ($r = $query->fetch()):
yield $r;
endwhile;
}
Then:
foreach ($connectDB() as $row)
echo $row['column1'], PHP_EOL;
echo $row['column2'], PHP_EOL;
echo $row['column3'], PHP_EOL;
endforeach;
Otherwise, just return an array, then extract:
function connectDB() {
// ...
$output = [];
$index = 0;
while ($r = $query->fetch()):
++$index;
foreach($r as $key => $value) {
$output[$name . '_' . $index] = $value;
}
endwhile;
return $output;
}
Then:
$vars = connectDB();
extract($vars);
;
echo $column1_1, PHP_EOL;
echo $column2_1, PHP_EOL;
echo $column3_1, PHP_EOL;
;
echo $column1_2, PHP_EOL;
echo $column2_2, PHP_EOL;
echo $column3_2, PHP_EOL;
The second purpose is very ugly.