How to Connect PHP to MySQL Database

If you are a beginner in website development, you might want to know how to use PHP script to connect to MySQL. That way, you can modify, view, or manage the tables created in the database. Keep reading this article as it will show you the easy ways to do it!

Creating a MySQL Database

This step is required in case you do not have a MySQL database. You can make a new one via Hostinger’s hPanel in a few easy steps:

1. Locate MySQL Databases menu under the Databases section.
2. Fill in the necessary fields and hit Create.
   

For instructions on how to create a MySQL database using cPanel, see this tutorial. Keep in mind, however, that these are just blank databases that you need to fill in with data before you can manipulate it.

Two Ways of Writing a PHP Script to Connect to MySQL

There are two methods to connect to an SQL database using PHP: MySQLi, and PDO.

One of the most important features they both support is prepared statements, which accelerates the time needed for MySQL to execute the same query multiple times. It can also be used to prevent SQL injection attacks when making changes to the database.

MySQLi stands for MySQL Improved. It is a MySQL-exclusive extension that adds new features to a MySQL database’s interface. MySQLi is both procedural and object-oriented, with the former being the attribute inherited from the older version of MySQL.

The original MySQL breaks down a task into linear, step-by-step procedures, which makes it more difficult to modify because then you have to edit the code from the top. Meanwhile, MySQLi sees data as a set of interchangeable objects with functions, allowing users to add or remove data easily.

PDO stands for PHP Data Object. Unlike MySQLi, PDO is object-oriented only and supports a number of different database types that use PHP, such as MySQL, MSSQL, Informix, and PostgreSQL.

Whichever method you use, you need the correct information so it will work with the database you have made. This is where the database details you have saved previously come in handy.

You also need the correct server name or hostname for the configuration. Hostinger uses “localhost” as its server’s hostname. In general, this is the name that you’d want to use if you uploaded your PHP script to the same server as the database.

In contrast, if you are connecting to a database from a remote location (for example, your computer) you have to use the IP address of the server. For more details, contact your hosting provider so they could provide you with the correct information on what to use as the hostname.

Connecting a PHP Script to MySQL using MySQLi

Here’s how to use MySQLi to connect a PHP script to MySQL:

1. Head over to File Manager -> public_html.
2. Create a New File by clicking the icon from the upper menu.
3. Save it as databaseconnect.php. You can replace the name with something else, just make sure it follows the same extension.
4. Double-click to open the file and fill it with the following lines of code. Change the first four values below <?php with the credentials you have noted earlier.

   <?php
   $servername = "localhost";
   $database = "databasename";
   $username = "username";
   $password = "password";
   
   // Create connection
   
   $conn = mysqli_connect($servername, $username, $password, $database);
   
   // Check connection
   
   if (!$conn) {
   
       die("Connection failed: " . mysqli_connect_error());
   
   }
   echo "Connected successfully";
   mysqli_close($conn);
   ?>

MySQLi Code Explained

The main method used in this script is mysqli_connect(). This is an internal PHP function to establish a new connection to a MySQL server.

At the very beginning of our code, we see a few variable declarations and values assigned to those variables. Usually, we need four of them to establish a proper connection: $servername, $database, $username, and $password. In the code, we have set our exact database details as values to those variables so they can be passed onto the function.

If the connection is not successful, the die() function is executed here, which basically kills our script and gives us a message that we have set. By default, it will say Connection failed followed by an exact error message describing the issue.

On the other hand, if the connection is successful, the code will print Connected successfully instead.

The last part of the code is mysqli_close, which will simply close the connection to a database manually. If not specified, the connection will close by itself once the script ends.

Connecting a PHP Script to MySQL using PDO

The methods to connect a PHP script to MySQL using PDO is similar to the previous one, but with a slight variation:

1. In the public_html, create a file named pdoconfig.php and insert the following code. As always, don’t forget to replace the placeholder values with your database information. Save and Close it once you’re done.

   <?php
       $host = 'localhost';
       $dbname = 'databasename';
       $username = 'username';
       $password = 'password';

2. Create another file named databaseconnect.php in the same directory, but with the following code. If you named the previous file differently, make sure to change the value of require_once.

   <?php
   require_once 'pdoconfig.php';
    
   try {
       $conn = new PDO("mysql:host=$host;dbname=$dbname", $username, $password);
       echo "Connected to $dbname at $host successfully.";
   } catch (PDOException $pe) {
       die("Could not connect to the database $dbname :" . $pe->getMessage());
   }

PDO Code Explained

A PDO database connection requires you to create a new PDO object with a Data Source Name (DSN), Username and Password.

The DSN defines the type of database, the name of the database, and any other information related to the database if required. These are the variables and values we stated inside the dbconfig.php file, referenced one time by the line require_once in the databaseconnect.php.

In the latter, you will find the try…catch.. code. This means that the script will try to connect using the code provided, and if there is a problem, the code in the catch section will run. You can use the catch block to display error messages or run alternate code if the try block fails.

If the connection is successful, it will print out the message “Connected to $dbname at $host successfully.” However, if the attempt fails, the catch code will show a simple error message and kill the script.

Checking Connectivity and Troubleshooting Common Errors

To check whether the connection is successful, access your domain like so: yourdomain/databaseconnect.php. If you name the PHP file with something different, make sure to change it accordingly.

You will see “Connected successfully” or its variants as the message if everything is running without any issue.

Now if the connection was not successful, you will see something different. The error messages look slightly different for MySQLi and PDO.

Incorrect Password Error

This error happens if we changed the password or any credential in the PHP code (but did not change it in the actual database).

In case you see an “Access denied” or “Could not connect to database” message accompanied by “(using password: YES)” at the end, the first thing to do is to check the database details. There could be a typo or a part that’s missing.

Cannot Connect to MySQL Server

If you get “Can’t connect to MySQL server on ‘server’ (110)” in MySQLi, it means the script did not get a response from a server. It happens when we set “server” instead of “localhost” as the $servername, and this name is not recognized.

The error message in PDO will look like something along the lines of Connection failed: SQLSTATE[Hy000] [2002] followed by more details stating that the host was not found. But the way to troubleshoot it is the same as the above.

And of course, it is always important to remember one golden rule of troubleshooting an error: checking your site error log.

The log can be found in the same folder where the script is running. For example, if we are running a script in public_html, we will find the error_log in the same folder.

Conclusion

In this tutorial, we have learned the very basic knowledge about how to connect a PHP script to a MySQL database using MySQLi and PHP Data Objects (PDO).

Hopefully, this guide was helpful for those who are just starting out with web development. After all, connecting to a database is the first, most important step when working with more advanced scripts and configurations.

Let us know in the comments below if you face any issue following this guide!