How to Use mysqli::init and mysqli::real_connect Functions Together to Establish a Database Connection

In PHP, we can manipulate MySQL databases through the MySQLi extension. mysqli provides both object-oriented and procedural interfaces for database operations. This article focuses on how the mysqli::init and mysqli::real_connect functions work together to establish a database connection.

1. Overview of the mysqli::init Function

mysqli::init is a method of the MySQLi class used to initialize a mysqli object. It returns a mysqli instance that can be used for subsequent database connection operations. This method is typically used to instantiate before establishing a database connection.

Example Code

$mysqli = new mysqli();

The code above creates a mysqli object but does not establish a connection to the database at this point.

2. Overview of the mysqli::real_connect Function

mysqli::real_connect is the function used to establish an actual connection to the MySQL database server. It requires information such as the database hostname, username, password, and database name.

Example Code

$mysqli->real_connect('gitbox.net', 'username', 'password', 'database_name');

The parameters of real_connect are:

• Hostname or IP address (e.g., 'gitbox.net')

• Username (e.g., 'username')

• Password (e.g., 'password')

• Database name (e.g., 'database_name')

If the connection is successful, the return value is true; otherwise, it returns false. Detailed connection error information can be retrieved through mysqli::connect_error or mysqli::connect_errno.

3. Using mysqli::init and mysqli::real_connect Together

To complete a database connection using mysqli::init and mysqli::real_connect, follow these steps:

Step 1: Instantiate the mysqli Object

First, initialize a mysqli object using mysqli::init. This step creates an empty mysqli object without establishing a database connection yet.

$mysqli = new mysqli();

Step 2: Establish Connection with mysqli::real_connect

Next, use the mysqli::real_connect method to initiate a connection request to the MySQL database server.

$mysqli->real_connect('gitbox.net', 'username', 'password', 'database_name');

If the connection succeeds, you can proceed with SQL queries and other database operations. If it fails, error information can be accessed via mysqli::connect_error.

Step 3: Check Whether the Connection Was Successful

After connecting to the database, it’s best to verify if the connection was successful. If the connection fails, output the error message and terminate the program.

if ($mysqli->connect_error) {
    die('Connection failed: ' . $mysqli->connect_error);
} else {
    echo 'Successfully connected to the database';
}

4. Complete Example Code

Below is a complete example demonstrating how to use mysqli::init and mysqli::real_connect to establish a database connection:

// Initialize connection
$mysqli->real_connect('gitbox.net', 'username', 'password', 'database_name');
// Check if connection was successful
if ($mysqli->connect_error) {
die('Connection failed: ' . $mysqli->connect_error);
} else {
echo 'Successfully connected to the database';
}
// Perform other database operations
$mysqli->close();
?>

5. Conclusion

mysqli::init and mysqli::real_connect can be used flexibly to handle database connections. By initializing a mysqli instance with mysqli::init and then establishing the connection using mysqli::real_connect, you gain precise control over the database connection process. If the connection fails, you can troubleshoot through the error messages. This approach allows for more fine-grained control in your applications.

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  mysqli