Database Configuration

Database Configuration in CodeIgniter (CodeIgniter 4)

CodeIgniter provides a simple and flexible way to configure and manage database connections using configuration files and environment variables.

1. Supported Databases

CodeIgniter 4 supports:

• MySQL / MariaDB

• PostgreSQL

• SQLite

• SQL Server

• Oracle

2. Database Configuration Location

You can configure the database in two ways:

1. Using .env file (Recommended)

2. Using app/Config/Database.php

3. Database Configuration Using .env (Recommended)

Rename the env file:

cp env .env

Edit .env:

database.default.hostname = localhost
database.default.database = mydatabase
database.default.username = root
database.default.password = 
database.default.DBDriver = MySQLi
database.default.DBPrefix =
database.default.port = 3306

✔ More secure
✔ Easy to change per environment

4. Database Configuration Using Database.php

File:

app/Config/Database.php

Example:

public $default = [
    'DSN'      => '',
    'hostname' => 'localhost',
    'username' => 'root',
    'password' => '',
    'database' => 'mydatabase',
    'DBDriver' => 'MySQLi',
    'DBPrefix' => '',
    'pConnect' => false,
    'DBDebug'  => true,
    'charset'  => 'utf8',
    'DBCollat' => 'utf8_general_ci',
    'port'     => 3306,
];

5. Setting Environment Mode

In .env:

CI_ENVIRONMENT = development

This enables:

• Detailed database error messages

• Debugging support

6. Connecting to the Database

Automatic Connection (Model)

$model = new UserModel();

Manual Connection

$db = \Config\Database::connect();

7. Testing Database Connection

Create a controller method:

public function testDB()
{
    $db = \Config\Database::connect();
    if ($db->connect()) {
        echo "Database Connected Successfully";
    }
}

8. Multiple Database Connections

Add another configuration:

public $testDB = [
    'hostname' => 'localhost',
    'username' => 'root',
    'password' => '',
    'database' => 'test_db',
    'DBDriver' => 'MySQLi'
];

Connect:

$db = \Config\Database::connect('testDB');

9. Database Prefix

database.default.DBPrefix = ci_

Table name:

ci_users

10. Enable Query Logging

In Database.php:

'DBDebug' => true,

Logs stored in:

writable/logs/

11. Security Best Practices

✅ Use .env for credentials
✅ Disable DBDebug in production
❌ Never commit .env to Git

Summary

• Configure DB using .env or Database.php

• Supports multiple databases

• Secure & environment-based setup

• Easy connection via models or services