Codeigniter 4 – Connecting to Database with Example

Connecting to a Database

- Use the db_connect() function to connect to a database.

Example:

$db = db_connect();

Specifying the Database Group

- Use the db_connect() function with the database group name to connect to a specific database.

Example:

$db = db_connect('my_group');

Specifying the Database Configuration

- Use the db_connect() function with the database configuration array to connect to a database.

Example:

$config = [
    'DSN' => '',
    'hostname' => 'localhost',
    'username' => 'root',
    'password' => '',
    'database' => 'my_database',
    'DBDriver' => 'MySQLi',
];
$db = db_connect($config);

Using the Database Object

- Use the $db object to execute queries and retrieve data.

Example:

$db->query('SELECT * FROM my_table');

Closing the Database Connection

- Use the db_close() function to close the database connection.

Example:

db_close($db);

Using the Query Builder

- Use the db_connect() function to connect to a database and then use the query builder to execute queries.

Example:

$db = db_connect();
$db->table('my_table')->get();

Using the Active Record Pattern

- Use the db_connect() function to connect to a database and then use the active record pattern to execute queries.

Example:

$db = db_connect();
$db->my_table->get();

I hope this helps! Let me know if you have any further questions or need more information.

Note: The Database class in CodeIgniter 4 provides a powerful and flexible way to interact with your database. It supports multiple database drivers, including MySQL, PostgreSQL, and SQLite.