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<h2 class="title">Character sets</h2>
<p class="para">
Ideally a proper character set will be set at the server level, and doing this is described
within the <a href="http://dev.mysql.com/doc/mysql/en/charset-configuration.html" class="link external">» Character Set Configuration</a>
section of the MySQL Server manual. Alternatively, each MySQL API offers a method to set
the character set at runtime.
</p>
<div class="caution"><strong class="caution">Caution</strong>
<h1 class="title">The character set and character escaping</h1>
<p class="para">
The character set should be understood and defined, as it has an affect on every
action, and includes security implications. For example, the escaping mechanism
(e.g., <span class="function"><a href="mysqli.real-escape-string.html" class="function">mysqli_real_escape_string()</a></span> for mysqli, <span class="function"><a href="function.mysql-real-escape-string.html" class="function">mysql_real_escape_string()</a></span>
for mysql, and <span class="methodname"><a href="pdo.quote.html" class="methodname">PDO::quote()</a></span> for PDO_MySQL) will adhere to
this setting. It is important to realize that these functions will not use the character
set that is defined with a query, so for example the following will not have an effect
on them:
</p>
</div>
<div class="example" id="example-1831">
<p><strong>Example #1 Problems with setting the character set with SQL</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$mysqli </span><span style="color: #007700">= new </span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_user"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_password"</span><span style="color: #007700">, </span><span style="color: #DD0000">"world"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Will NOT affect $mysqli->real_escape_string();<br /></span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">query</span><span style="color: #007700">(</span><span style="color: #DD0000">"SET NAMES utf8"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Will NOT affect $mysqli->real_escape_string();<br /></span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">query</span><span style="color: #007700">(</span><span style="color: #DD0000">"SET CHARACTER SET utf8"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// But, this will affect $mysqli->real_escape_string();<br /></span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">set_charset</span><span style="color: #007700">(</span><span style="color: #DD0000">'utf8'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// But, this will NOT affect it (utf-8 vs utf8) -- don't use dashes here<br /></span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">set_charset</span><span style="color: #007700">(</span><span style="color: #DD0000">'utf-8'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<p class="para">
Below are examples that demonstrate how to properly alter the character set at runtime
using each API.
</p>
<blockquote class="note"><p><strong class="note">Note</strong>:
<strong>Possible UTF-8 confusion</strong><br />
<p class="para">
Because character set names in MySQL do not contain dashes, the string
"utf8" is valid in MySQL to set the character set to UTF-8. The string
"utf-8" is not valid, as using "utf-8" will fail to change the
character set.
</p>
</p></blockquote>
<div class="example" id="example-1832">
<p><strong>Example #2 Setting the character set example: mysqli</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$mysqli </span><span style="color: #007700">= new </span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_user"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_password"</span><span style="color: #007700">, </span><span style="color: #DD0000">"world"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Initial character set: %s\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">character_set_name</span><span style="color: #007700">());<br /><br />if (!</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">set_charset</span><span style="color: #007700">(</span><span style="color: #DD0000">'utf8'</span><span style="color: #007700">)) {<br /> </span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Error loading character set utf8: %s\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">error</span><span style="color: #007700">);<br /> exit;<br />}<br /><br />echo </span><span style="color: #DD0000">"New character set information:\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">( </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">get_charset</span><span style="color: #007700">() );<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="example" id="example-1833">
<p><strong>Example #3 Setting the character set example: <a href="ref.pdo-mysql.connection.html" class="link">pdo_mysql</a></strong></p>
<div class="example-contents"><p>
Note: This only works as of PHP 5.3.6.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$pdo </span><span style="color: #007700">= new </span><span style="color: #0000BB">PDO</span><span style="color: #007700">(</span><span style="color: #DD0000">"mysql:host=localhost;dbname=world;charset=utf8"</span><span style="color: #007700">, </span><span style="color: #DD0000">'my_user'</span><span style="color: #007700">, </span><span style="color: #DD0000">'my_pass'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="example" id="example-1834">
<p><strong>Example #4 Setting the character set example: mysql</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$conn </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">"my_user"</span><span style="color: #007700">, </span><span style="color: #DD0000">"my_pass"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$db </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_select_db</span><span style="color: #007700">(</span><span style="color: #DD0000">"world"</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #DD0000">'Initial character set: ' </span><span style="color: #007700">. </span><span style="color: #0000BB">mysql_client_encoding</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br />if (!</span><span style="color: #0000BB">mysql_set_charset</span><span style="color: #007700">(</span><span style="color: #DD0000">'utf8'</span><span style="color: #007700">, </span><span style="color: #0000BB">$conn</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"Error: Unable to set the character set.\n"</span><span style="color: #007700">;<br /> exit;<br />}<br /><br />echo </span><span style="color: #DD0000">'Your current character set is: ' </span><span style="color: #007700">. </span><span style="color: #0000BB">mysql_client_encoding</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
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