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Configuring Database Connections in CodeIgniter

How to configuring database connections in CodeIgniter, with additional information

Table of Contents​

Introduction ​

CodeIgniter is a powerful PHP framework that provides a simple and elegant way to handle database interactions. In this tutorial, we will learn how to configure database connections in CodeIgniter and perform common database operations.

Setting up the Database Configuration ​

To configure the database connection in CodeIgniter, follow these steps:

Database Types ​

CodeIgniter supports various database types, including MySQL, PostgreSQL, SQLite, Oracle, and more. To specify the database type, set the 'dbdriver' parameter in the database.php configuration file accordingly.

Database Connection Parameters ​

Open the application/config/database.php file and modify the following parameters according to your database setup:

  • 'hostname': The hostname or IP address of your database server.
  • 'username': The username to connect to the database.
  • 'password': The password to connect to the database.
  • 'database': The name of the database you want to connect to.
  • 'dbdriver': The type of database driver to use (e.g., 'mysqli' or 'pdo').

You can also configure additional parameters such as port, character set, and more depending on your database requirements.

Connecting to the Database ​

To establish a database connection in CodeIgniter, follow these steps:

  1. Load the database library by adding the following line in your controller or model:

    $this->load->database();

  2. Once the library is loaded, you can access the database object using $this->db and perform various database operations.

Executing Queries ​

CodeIgniter provides a convenient query builder class that allows you to build and execute database queries easily. Here are examples of different types of queries:

Select Queries ​

To perform a select query and retrieve data from the database, you can use the following code:

$query = $this->db->get('users');
if ($query->num_rows() > 0) {
    foreach ($query->result() as $row) {
        echo $row->username;
    }
}

Insert Queries ​

To insert data into a table, you can use the following code:

$data = array(
    'username' => 'john',
    'email' => 'john@example.com',
    'password' => 'secret'
);

$this->db->insert('users', $data);

Update Queries ​

To update data in a table, you can use the following code:

$data = array(
    'email' => 'new_email@example.com',
    'password' => 'new_secret'
);

$this->db->where('username', 'john');
$this->db->update('users', $data);

Delete Queries ​

To delete data from a table, you can use the following code:

$this->db->where('username', 'john');
$this->db->delete('users');

Closing the Database Connection ​

CodeIgniter automatically closes the database connection when the script finishes executing. However, if you want to manually close the connection, you can use the following code:

$this->db->close();

Conclusion ​

In this tutorial, we have learned how to configure and establish database connections in CodeIgniter. We have explored various types of queries such as select, insert, update, and delete. Now you can leverage the power of CodeIgniter to interact with databases efficiently.