Error on calling a function with connection to SQL server - php

Question

I am getting
Fatal error: Call to a member function query() on a non-object in
C:...\test.php on line 27
after calling callQuery2.
<?php
dbConnect();
callQuery1();
callQuery2();
function callQuery1(){
// SQL query
$q = "SELECT * FROM table1 WHERE name like 'john%' ";
// Execute query
$data1 = exeQuery($q);
}
function callQuery2(){
// SQL query
$q = "SELECT * FROM table2 WHERE event = 'holiday' ";
// Execute query
$data2 = exeQuery($q);
}
// Execute SQL Query
function exeQuery($qry) {
global $pdo;
####### LINE 27 #######
$stmt = $pdo->query($qry);
if($stmt = $pdo->prepare($qry)) {
$stmt->execute();
$data = $stmt->fetchAll(PDO::FETCH_ASSOC);
$stmt->closeCursor();
return $data;
}
}
// database connection
function dbConnect(){
$DBSERVER = "***";
$DBUSER = "***";
$DBPASS = "***";
$DBNAME = "***";
// OBDC
try {
$pdo = new PDO("odbc:DRIVER={SQL Server};Server={$DBSERVER};Database={$DBNAME}", $DBUSER, $DBPASS);
// set the PDO error mode to exception
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
//die(json_encode(array('outcome' => true)));
}
catch(PDOException $ex) {
//die(json_decode(array('outcome' => false, 'message' => 'Unable to connect')));
}
}
?>
Why the error only appears after at that time?
Is the a better way to do this?
Regards,
Elio Fernandes

Answer 1

This would be better encapsulated without the global $pdo; part. Instead return the PDO object from your connect method, and pass it to the others, to be used.
N.B. I've deliberately given the variables different names in different places, to illustrate that the name doesn't have to be the same when it's passed from one scope to another, it's the object that's passed which is important. You might perhaps consider using consistent names though, to make it easier to comprehend the code later, and trace the object through the flow.
<?php
$dbConn = dbConnect();
callQuery1($dbConn);
callQuery2($dbConn);
function callQuery1($db){
// SQL query
$q = "SELECT * FROM table1 WHERE name like 'john%' ";
// Execute query
$data1 = exeQuery($q, $db);
}
function callQuery2($db){
// SQL query
$q = "SELECT * FROM table2 WHERE event = 'holiday' ";
// Execute query
$data2 = exeQuery($q, $db);
}
// Execute SQL Query
function exeQuery($qry, $pdo) {
####### LINE 27 #######
$stmt = $pdo->query($qry);
if($stmt = $pdo->prepare($qry)) {
$stmt->execute();
$data = $stmt->fetchAll(PDO::FETCH_ASSOC);
$stmt->closeCursor();
return $data;
}
}
// database connection
function dbConnect(){
$DBSERVER = "***";
$DBUSER = "***";
$DBPASS = "***";
$DBNAME = "***";
// OBDC
try {
$pdo = new PDO("odbc:DRIVER={SQL Server};Server={$DBSERVER};Database={$DBNAME}", $DBUSER, $DBPASS);
// set the PDO error mode to exception
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
return $pdo;
}
catch(PDOException $ex) {
//die(json_decode(array('outcome' => false, 'message' => 'Unable to connect')));
}
}
?>