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Codeigniter Database configuration

Last modified on: September 9, 2025

<h1 data-start="462" data-end="507">🗄️ Database Configuration in CodeIgniter</h1>
<h2 data-start="509" data-end="540">🔎 Why Configure Database?</h2>
<p data-start="541" data-end="689">Database configuration allows CodeIgniter to connect with databases like <strong data-start="614" data-end="660">MySQL, MariaDB, PostgreSQL, SQLite, Oracle</strong> etc. This is required for:</p>
<ul data-start="690" data-end="807">
<li data-start="690" data-end="718">
<p data-start="692" data-end="718">Models (CRUD operations)</p>
</li>
<li data-start="719" data-end="736">
<p data-start="721" data-end="736">Query Builder</p>
</li>
<li data-start="737" data-end="771">
<p data-start="739" data-end="771">Session handling with database</p>
</li>
<li data-start="772" data-end="807">
<p data-start="774" data-end="807">Migrations and seeding (in CI4)</p>
</li>
</ul>
<hr data-start="809" data-end="812" />
<h2 data-start="814" data-end="864">📂 1. Database Configuration in CodeIgniter 3</h2>
<h3 data-start="866" data-end="896">Step 1: Open Config File</h3>
<p data-start="897" data-end="904">File:</p>
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<pre class="language-php"><code>application/config/database.php
</code></pre>
</div>
</div>
</div>
</div>
<h3 data-start="946" data-end="990">Step 2: Edit Default Database Settings</h3>
<p data-start="992" data-end="1010">Example (MySQL):</p>
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<pre class="language-php"><code>$db['default'] = array(
    'dsn'      =&gt; '',
    'hostname' =&gt; 'localhost',
    'username' =&gt; 'root',
    'password' =&gt; '',
    'database' =&gt; 'ci_db',
    'dbdriver' =&gt; 'mysqli',
    'dbprefix' =&gt; '',
    'pconnect' =&gt; FALSE,
    'db_debug' =&gt; (ENVIRONMENT !== 'production'),
    'cache_on' =&gt; FALSE,
    'cachedir' =&gt; '',
    'char_set' =&gt; 'utf8',
    'dbcollat' =&gt; 'utf8_general_ci',
    'swap_pre' =&gt; '',
    'encrypt'  =&gt; FALSE,
    'compress' =&gt; FALSE,
    'stricton' =&gt; FALSE,
    'failover' =&gt; array(),
    'save_queries' =&gt; TRUE
);
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="1564" data-end="1581">👉 Explanation:</p>
<ul data-start="1582" data-end="1821">
<li data-start="1582" data-end="1634">
<p data-start="1584" data-end="1634"><code data-start="1584" data-end="1594">hostname</code> &rarr; Database host (usually <code data-start="1620" data-end="1631">localhost</code>)</p>
</li>
<li data-start="1635" data-end="1697">
<p data-start="1637" data-end="1697"><code data-start="1637" data-end="1647">username</code> &rarr; DB username (<code data-start="1663" data-end="1669">root</code> by default in XAMPP/WAMP)</p>
</li>
<li data-start="1698" data-end="1726">
<p data-start="1700" data-end="1726"><code data-start="1700" data-end="1710">password</code> &rarr; DB password</p>
</li>
<li data-start="1727" data-end="1762">
<p data-start="1729" data-end="1762"><code data-start="1729" data-end="1739">database</code> &rarr; Your database name</p>
</li>
<li data-start="1763" data-end="1821">
<p data-start="1765" data-end="1821"><code data-start="1765" data-end="1775">dbdriver</code> &rarr; <code data-start="1778" data-end="1786">mysqli</code>, <code data-start="1788" data-end="1797">postgre</code>, <code data-start="1799" data-end="1807">sqlite</code>, <code data-start="1809" data-end="1814">pdo</code> etc.</p>
</li>
</ul>
<h3 data-start="1823" data-end="1858">Step 3: Load Database Library</h3>
<p data-start="1859" data-end="1903">In <code data-start="1862" data-end="1895">application/config/autoload.php</code>, add:</p>
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<pre class="language-php"><code>$autoload['libraries'] = array('database');
</code></pre>
</div>
</div>
</div>
</div>
<p data-start="1960" data-end="2031">Now your app is ready to use <code data-start="1989" data-end="2000">$this-&gt;db</code> inside models &amp; controllers.</p>
<hr data-start="2033" data-end="2036" />
<h2 data-start="2038" data-end="2088">📂 2. Database Configuration in CodeIgniter 4</h2>
<p data-start="2090" data-end="2168">In CI4, configuration is done in <strong data-start="2123" data-end="2136">.env file</strong> or <code data-start="2140" data-end="2165">app/Config/Database.php</code>.</p>
<h3 data-start="2170" data-end="2213">Step 1: Use <code data-start="2186" data-end="2192">.env</code> File (Recommended)</h3>
<p data-start="2215" data-end="2237">Open <code data-start="2220" data-end="2226">.env</code> and set:</p>
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<pre class="language-php"><code>database.default.hostname = localhost
database.default.database = ci_db
database.default.username = root
database.default.password = 
database.default.DBDriver = MySQLi
database.default.DBPrefix =
</code></pre>
</div>
</div>
</div>
</div>
<h3 data-start="2447" data-end="2486">Step 2: Alternative (Config File)</h3>
<p data-start="2488" data-end="2521">Edit <code data-start="2493" data-end="2518">app/Config/Database.php</code>:</p>
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<pre class="language-php"><code>public $default = [
    'DSN'      =&gt; '',
    'hostname' =&gt; 'localhost',
    'username' =&gt; 'root',
    'password' =&gt; '',
    'database' =&gt; 'ci_db',
    'DBDriver' =&gt; 'MySQLi',
    'DBPrefix' =&gt; '',
    'pConnect' =&gt; false,
    'DBDebug'  =&gt; (ENVIRONMENT !== 'production'),
    'cacheOn'  =&gt; false,
    'cacheDir' =&gt; '',
    'charset'  =&gt; 'utf8',
    'DBCollat' =&gt; 'utf8_general_ci',
    'swapPre'  =&gt; '',
    'encrypt'  =&gt; false,
    'compress' =&gt; false,
    'strictOn' =&gt; false,
    'failover' =&gt; [],
    'port'     =&gt; 3306,
];
</code></pre>
</div>
</div>
</div>
</div>
<hr data-start="3063" data-end="3066" />
<h2 data-start="3068" data-end="3095">📊 Supported Databases</h2>
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<div class="_tableWrapper_1rjym_13 group flex w-fit flex-col-reverse" tabindex="-1">
<table class="w-fit min-w-(--thread-content-width)" data-start="3097" data-end="3469">
<thead data-start="3097" data-end="3141">
<tr data-start="3097" data-end="3141">
<th data-start="3097" data-end="3108" data-col-size="sm">Driver</th>
<th data-start="3108" data-end="3124" data-col-size="sm">CodeIgniter 3</th>
<th data-start="3124" data-end="3141" data-col-size="sm">CodeIgniter 4</th>
</tr>
</thead>
<tbody data-start="3187" data-end="3469">
<tr data-start="3187" data-end="3231">
<td data-start="3187" data-end="3198" data-col-size="sm">MySQLi</td>
<td data-start="3198" data-end="3214" data-col-size="sm">✅</td>
<td data-start="3214" data-end="3231" data-col-size="sm">✅</td>
</tr>
<tr data-start="3232" data-end="3276">
<td data-start="3232" data-end="3245" data-col-size="sm">PostgreSQL</td>
<td data-start="3245" data-end="3259" data-col-size="sm">✅</td>
<td data-start="3259" data-end="3276" data-col-size="sm">✅</td>
</tr>
<tr data-start="3277" data-end="3321">
<td data-start="3277" data-end="3288" data-col-size="sm">SQLite</td>
<td data-start="3288" data-end="3304" data-col-size="sm">✅</td>
<td data-start="3304" data-end="3321" data-col-size="sm">✅</td>
</tr>
<tr data-start="3322" data-end="3366">
<td data-start="3322" data-end="3333" data-col-size="sm">ODBC</td>
<td data-start="3333" data-end="3349" data-col-size="sm">✅</td>
<td data-start="3349" data-end="3366" data-col-size="sm">✅</td>
</tr>
<tr data-start="3367" data-end="3411">
<td data-start="3367" data-end="3378" data-col-size="sm">SQLSRV</td>
<td data-start="3378" data-end="3394" data-col-size="sm">✅</td>
<td data-start="3394" data-end="3411" data-col-size="sm">✅</td>
</tr>
<tr data-start="3412" data-end="3469">
<td data-start="3412" data-end="3423" data-col-size="sm">Oracle</td>
<td data-start="3423" data-end="3438" data-col-size="sm">✅ (via ODBC)</td>
<td data-start="3438" data-end="3469" data-col-size="sm">⚠️ Not officially supported</td>
</tr>
</tbody>
</table>
</div>
</div>
<hr data-start="3471" data-end="3474" />
<h2 data-start="3476" data-end="3497">✅ Best Practices</h2>
<ol data-start="3499" data-end="3944">
<li data-start="3499" data-end="3554">
<p data-start="3502" data-end="3554">Use <code data-start="3506" data-end="3512">.env</code> file in CI4 to keep credentials secure.</p>
</li>
<li data-start="3555" data-end="3620">
<p data-start="3558" data-end="3620">Always set a <strong data-start="3571" data-end="3593">strong DB password</strong> (avoid empty passwords).</p>
</li>
<li data-start="3621" data-end="3700">
<p data-start="3624" data-end="3700">Disable <code data-start="3632" data-end="3642">db_debug</code> in <strong data-start="3646" data-end="3660">production</strong> to prevent query errors leaking info.</p>
</li>
<li data-start="3701" data-end="3854">
<p data-start="3704" data-end="3770">Use <code data-start="3708" data-end="3717">utf8mb4</code> instead of <code data-start="3729" data-end="3735">utf8</code> for full Unicode (emojis, etc.).</p>
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<pre class="language-php"><code>'charset'  =&gt; 'utf8mb4',
'DBCollat' =&gt; 'utf8mb4_general_ci',
</code></pre>
</div>
</div>
</div>
</div>
</li>
<li data-start="3855" data-end="3944">
<p data-start="3858" data-end="3944">For multiple DB connections, create more groups in <code data-start="3909" data-end="3923">database.php</code> or <code data-start="3927" data-end="3941">Database.php</code>.</p>
</li>
</ol>
<hr data-start="3946" data-end="3949" />
<h2 data-start="3951" data-end="3984">🎯 Example Usage (CI3 &amp; CI4)</h2>
<h3 data-start="3986" data-end="4018">Query in Controller (CI3):</h3>
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<pre class="language-php"><code>$query = $this-&gt;db-&gt;get('users');
foreach ($query-&gt;result() as $row) {
    echo $row-&gt;username;
}
</code></pre>
</div>
</div>
</div>
</div>
<h3 data-start="4129" data-end="4161">Query in Controller (CI4):</h3>
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<pre class="language-php"><code>$db = \Config\Database::connect();
$query = $db-&gt;query("SELECT * FROM users");
foreach ($query-&gt;getResult() as $row) {
    echo $row-&gt;username;
}
</code></pre>
</div>
</div>
</div>
</div>
<hr data-start="4320" data-end="4323" />
<p data-start="4325" data-end="4411">✅ Now your CodeIgniter app is fully connected to the database and ready for queries.</p>

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