How I call my mysqli in order page? - php

Question

I have this in db.php page:
function db_connect(){ $link = new mysqli(localhost, user, pass, table); }
And this is in other page:
require_once("db.php");
function register($username, $email, $password){
global $link;
$query = "INSERT INTO proyecto.user (username, password, email)
VALUES ('$username', '$password', '$email')";
$result = mysqli_query($link, $query);
}
But it doesn't work when I call "register". How should I call the function "db_connect"?

Answer 1

You can do it like this (PDO connection):
// Usage: $db = connectToDatabase($dbHost, $dbName, $dbUsername, $dbPassword);
// Pre: $dbHost is the database hostname,
// $dbName is the name of the database itself,
// $dbUsername is the username to access the database,
// $dbPassword is the password for the user of the database.
// Post: $db is an PDO connection to the database, based on the input parameters.
function connectToDatabase($dbHost, $dbName, $dbUsername, $dbPassword)
{
try
{
return new PDO("mysql:host=$dbHost;dbname=$dbName;charset=UTF-8", $dbUsername, $dbPassword);
}
catch(PDOException $PDOexception)
{
exit("<p>An error ocurred: Can't connect to database. </p><p>More preciesly: ". $PDOexception->getMessage(). "</p>");
}
}
And then init the variables:
$host = 'localhost';
$user = 'root';
$dataBaseName = 'databaseName';
$pass = '';
Now you can access your database via
$db = connectToDatabase($host , $databaseName, $user, $pass); // You can make it be a global variable if you want to access it from somewhere else.
You can make it become a global variable if you want.
$GLOBALS['db'] = $db;
Note that this is pdo, an example of a PDO database operation for your case, note that this uses prepared statements and is therefor quite safe from sql injections, and is quite easy to use:
function register($username, $email, $password){
$query = "INSERT INTO user (username, password, email) VALUES (:username, :password, :email)"; // Construct the query, making it accept a prepared variable search.
$statement = $db->prepare($query); // Prepare the query.
$result = $statement->execute(array(
':username' => $username,
':password' => $password,
':email' => $email
)); // Here you insert the variable, by executing it 'into' the prepared query.
if($result)
{
return true;
}
return false
}
And you can call it like this:
$registerSuccess = register($username, $email, $password);

Answer 2

have db_connect() return the $link, or make $link global in db_connect()
function db_connect() {
return new mysqli(localhost, user, pass, table);
}
function register($username, $email, $password) {
$link = db_connect();
$query = "INSERT INTO proyecto.user (username, password, email)
VALUES ('$username', '$password', '$email')";
$result = mysqli_query($link, $query);
}