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<title>Dual procedural and object-oriented interface</title>
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<h2 class="title">Dual procedural and object-oriented interface</h2>
<p class="para">
The mysqli extension features a dual interface. It supports the procedural
and object-oriented programming paradigm.
</p>
<p class="para">
Users migrating from the old mysql extension may prefer the procedural
interface. The procedural interface is similar to that of the old mysql
extension. In many cases, the function names differ only by prefix.
Some mysqli functions take a connection handle as their first argument,
whereas matching functions in the old mysql interface take
it as an optional last argument.
</p>
<p class="para">
<div class="example" id="example-1618">
<p><strong>Example #1 Easy migration from the old mysql extension</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$mysqli </span><span style="color: #007700">= </span><span style="color: #0000BB">mysqli_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"example.com"</span><span style="color: #007700">, </span><span style="color: #DD0000">"user"</span><span style="color: #007700">, </span><span style="color: #DD0000">"password"</span><span style="color: #007700">, </span><span style="color: #DD0000">"database"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$res </span><span style="color: #007700">= </span><span style="color: #0000BB">mysqli_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">, </span><span style="color: #DD0000">"SELECT 'Please, do not use ' AS _msg FROM DUAL"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">mysqli_fetch_assoc</span><span style="color: #007700">(</span><span style="color: #0000BB">$res</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #DD0000">'_msg'</span><span style="color: #007700">];<br /><br /></span><span style="color: #0000BB">$mysql </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"root"</span><span style="color: #007700">, </span><span style="color: #DD0000">""</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">mysql_select_db</span><span style="color: #007700">(</span><span style="color: #DD0000">"test"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$res </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"SELECT 'the mysql extension for new developments.' AS _msg FROM DUAL"</span><span style="color: #007700">, </span><span style="color: #0000BB">$mysql</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_fetch_assoc</span><span style="color: #007700">(</span><span style="color: #0000BB">$res</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #DD0000">'_msg'</span><span style="color: #007700">];<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Please, do not use the mysql extension for new developments.
</pre></div>
</div>
</div>
</p>
<p class="para">
<em class="emphasis">The object-oriented interface</em>
</p>
<p class="para">
In addition to the classical procedural interface, users can choose to use
the object-oriented interface. The documentation is organized using
the object-oriented interface. The object-oriented interface shows functions
grouped by their purpose, making it easier to get started. The reference section
gives examples for both syntax variants.
</p>
<p class="para">
There are no significant performance differences between the two interfaces.
Users can base their choice on personal preference.
</p>
<p class="para">
<div class="example" id="example-1619">
<p><strong>Example #2 Object-oriented and procedural interface</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$mysqli </span><span style="color: #007700">= </span><span style="color: #0000BB">mysqli_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"example.com"</span><span style="color: #007700">, </span><span style="color: #DD0000">"user"</span><span style="color: #007700">, </span><span style="color: #DD0000">"password"</span><span style="color: #007700">, </span><span style="color: #DD0000">"database"</span><span style="color: #007700">);<br />if (</span><span style="color: #0000BB">mysqli_connect_errno</span><span style="color: #007700">(</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"Failed to connect to MySQL: " </span><span style="color: #007700">. </span><span style="color: #0000BB">mysqli_connect_error</span><span style="color: #007700">();<br />}<br /><br /></span><span style="color: #0000BB">$res </span><span style="color: #007700">= </span><span style="color: #0000BB">mysqli_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">, </span><span style="color: #DD0000">"SELECT 'A world full of ' AS _msg FROM DUAL"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">mysqli_fetch_assoc</span><span style="color: #007700">(</span><span style="color: #0000BB">$res</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #DD0000">'_msg'</span><span style="color: #007700">];<br /><br /></span><span style="color: #0000BB">$mysqli </span><span style="color: #007700">= new </span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"example.com"</span><span style="color: #007700">, </span><span style="color: #DD0000">"user"</span><span style="color: #007700">, </span><span style="color: #DD0000">"password"</span><span style="color: #007700">, </span><span style="color: #DD0000">"database"</span><span style="color: #007700">);<br />if (</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">connect_errno</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"Failed to connect to MySQL: " </span><span style="color: #007700">. </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">connect_error</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">$res </span><span style="color: #007700">= </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">query</span><span style="color: #007700">(</span><span style="color: #DD0000">"SELECT 'choices to please everybody.' AS _msg FROM DUAL"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">$res</span><span style="color: #007700">-></span><span style="color: #0000BB">fetch_assoc</span><span style="color: #007700">();<br />echo </span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #DD0000">'_msg'</span><span style="color: #007700">];<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
A world full of choices to please everybody.
</pre></div>
</div>
</div>
</p>
<p class="para">
The object oriented interface is used for the quickstart because the
reference section is organized that way.
</p>
<p class="para">
<em class="emphasis">Mixing styles</em>
</p>
<p class="para">
It is possible to switch between styles at any time. Mixing both styles is
not recommended for code clarity and coding style reasons.
</p>
<p class="para">
<div class="example" id="example-1620">
<p><strong>Example #3 Bad coding style</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$mysqli </span><span style="color: #007700">= new </span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"example.com"</span><span style="color: #007700">, </span><span style="color: #DD0000">"user"</span><span style="color: #007700">, </span><span style="color: #DD0000">"password"</span><span style="color: #007700">, </span><span style="color: #DD0000">"database"</span><span style="color: #007700">);<br />if (</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">connect_errno</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"Failed to connect to MySQL: " </span><span style="color: #007700">. </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">connect_error</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">$res </span><span style="color: #007700">= </span><span style="color: #0000BB">mysqli_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">, </span><span style="color: #DD0000">"SELECT 'Possible but bad style.' AS _msg FROM DUAL"</span><span style="color: #007700">);<br />if (!</span><span style="color: #0000BB">$res</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"Failed to run query: (" </span><span style="color: #007700">. </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">errno </span><span style="color: #007700">. </span><span style="color: #DD0000">") " </span><span style="color: #007700">. </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">error</span><span style="color: #007700">;<br />}<br /><br />if (</span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">$res</span><span style="color: #007700">-></span><span style="color: #0000BB">fetch_assoc</span><span style="color: #007700">()) {<br /> echo </span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #DD0000">'_msg'</span><span style="color: #007700">];<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Possible but bad style.
</pre></div>
</div>
</div>
</p>
<p class="para">
<em class="emphasis">See also</em>
</p>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="methodname"><a href="mysqli.construct.html" class="methodname">mysqli::__construct()</a></span></li>
<li class="member"> <span class="methodname"><a href="mysqli.query.html" class="methodname">mysqli::query()</a></span></li>
<li class="member"> <span class="methodname"><a href="mysqli-result.fetch-assoc.html" class="methodname">mysqli_result::fetch_assoc()</a></span></li>
<li class="member"><a href="mysqli.connect-errno.html" class="link">$mysqli::connect_errno</a></li>
<li class="member"><a href="mysqli.connect-error.html" class="link">$mysqli::connect_error</a></li>
<li class="member"><a href="mysqli.errno.html" class="link">$mysqli::errno</a></li>
<li class="member"><a href="mysqli.error.html" class="link">$mysqli::error</a></li>
<li class="member"><a href="mysqli.summary.html" class="link">The MySQLi Extension Function Summary</a></li>
</ul>
</p>
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