In this tutorial, you will learn how to use PHP to connect to a MySQL database and execute queries to retrieve and manipulate data.
PHP is a popular programming language used in web development to interact with databases. If you want to use PHP to connect to a MySQL database, there are a few steps you need to follow.
Prerequisites
Before you begin, make sure you have the following requirements:
- A running MySQL server
- A database that you want to connect to
- PHP installed on your machine
Establishing a Connection
To connect to a MySQL database using PHP, you must use the mysqli_connect function. This function takes four parameters: the server hostname, the username, the password, and the database name. For example:
$conn = mysqli_connect('localhost', 'username', 'password', 'database_name');
The mysqli_connect function will return a connection resource if the connection is successful, or false if the connection fails.
It's a good idea to check the return value of the mysqli_connect function and handle any errors that may occur. You could do this using the mysqli_connect_error function, which returns the error message if a connection error occurred. For example:
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
Executing Queries
Once you connect to the MySQL server, you can use the mysqli_query function to execute SQL statements and retrieve data from the database. For example:
$result = mysqli_query($conn, 'SELECT * FROM users');
The mysqli_query function returns a result set if the query was successful or false if the query failed.
To retrieve the data from the result set, you can use functions like mysqli_fetch_assoc, which returns an associative array of the current row. You can loop through the result set using a while loop until no more rows are left. For example:
while ($row = mysqli_fetch_assoc($result)) {
// Do something with the row data
}
It's also a good idea to check the return value of the mysqli_query function and handle any possible errors. You can do this using the mysqli_error function, which returns the error message if a query error occurs. For example:
if (!$result) {
die("Query failed: " . mysqli_error($conn));
}
Closing the Connection
When you're done using the connection to the MySQL server, closing it to free up resources is a good idea. You can do this using the mysqli_close function:
mysqli_close($conn);