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PHP

Konrad Pilch
Konrad Pilch
2,435 Points
Posted by Konrad Pilch
Konrad Pilch
2,435 Points

Whats wrong with this code?

What is wrong with this code? it makes no effect :

FILE NAME: connect.inc.php

CODE:

<?php

$mysqli_host = 'localhost';
$mysqli_user = 'root';
$mysqli_pass = 'root';

$mysqli_db = 'a_database';

if (!mysqli_connect($mysqli_host, $mysqli_user, $mysqli_pass) || !mysqli_select_db($mysqli_db)) {
    die(mysqli_error());
}

?>

Index:

<?php
require 'connect.inc.php';



?>

3 Answers

Ash Matadeen
Ash Matadeen
Courses Plus Student 7,185 Points

Ok, so a couple of issues here.

  1. The mysqli_select_db() function expects 2 arguments, in addition to the database name, you need to pass it the database link - this is the object returned by mysql_connect().

  2. The mysqli_error() function also expects the object returned by mysql_select_db() as argument.

Try this:

<?php
error_reporting(E_ALL);  // reports all errors to make it easier to debug

$connection = mysqli_connect($mysqli_host, $mysqli_user, $mysqli_pass);

if (!$connection) {
    die("Could not connect to the database server");
} elseif (!mysqli_select_db($connection, $mysqli_db)) {
    echo "Could not select the database<br />";
    die(mysqli_error($connection));
} else {
    echo "Connection successful";
}
?>

If you then change the database name, or login credentials, you should see the relevant error.

Konrad Pilch
Konrad Pilch
2,435 Points
Konrad Pilch
Konrad Pilch
2,435 Points

Thank you ! It worked. But why my code didnt work? whats the difference?

Ash Matadeen
PLUS
Ash Matadeen
Courses Plus Student 7,185 Points
Ash Matadeen
Ash Matadeen
Courses Plus Student 7,185 Points

Konrad Pilch The key difference is in the arguments that you pass through to mysqli_select_db() and mysqli_error().

<?php 
mysqli_select_db($mysqli_db); // will not work as it's missing the $connection argument
mysqli_select_db($connection, $mysqli_db); // will work

mysqli_error(); // will not work as it's missing the $connection argument
mysqli_error($connection); // will work
?>

It's worth having a look at the documentation for those two functions: mysqli_select_db() documentation mysqli_error() documentation

Ash Matadeen
PLUS
Ash Matadeen
Courses Plus Student 7,185 Points
Ash Matadeen
Ash Matadeen
Courses Plus Student 7,185 Points

If you don't see any errors when loading this script, it means that your connection to the database was successful.

<?php
if (!mysqli_connect($mysqli_host, $mysqli_user, $mysqli_pass) || !mysqli_select_db($mysqli_db)) {
    die(mysqli_error());
}
?>

This bit of code stops the script and displays any errors BUT only if it has either failed to connect to the mysql server or failed to select the database.

Konrad Pilch
Konrad Pilch
2,435 Points
Konrad Pilch
Konrad Pilch
2,435 Points

yes but then i did make and error for the purpose of checking and i had no errors shown .