mysqli.change-user.html

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     <span class="term"><i><tt class="parameter">database</tt></i>
</span>

     <dd>

      <p class="para">
       The database to change to.
      </p>
      <p class="para">
       If desired, the <b><tt>NULL</tt></b> value may be passed resulting in only changing
       the user and not selecting a database. To select a database in this
       case use the <a href="mysqli.select-db.html" class="function">mysqli_select_db()</a> function.
      </p>
     </dd>

    </dt>

   </dl>

  </p>
 </div>


 <div class="refsect1 returnvalues">
  <h3 class="title">Return Values</h3>
  <p class="para">
   Returns <b><tt>TRUE</tt></b> on success or <b><tt>FALSE</tt></b> on failure.
  </p>
 </div>


 <div class="refsect1 notes">
  <h3 class="title">Notes</h3>
  <blockquote><p><b class="note">Note</b>: 
   
    Using this command will always cause the current database connection to
    behave as if was a completely new database connection, regardless of if
    the operation was completed successfully. This reset includes performing
    a rollback on any active transactions, closing all temporary tables, and
    unlocking all locked tables.
   <br />
  </p></blockquote>
 </div>


 <div class="refsect1 examples">
  <h3 class="title">Examples</h3>
   <div class="example">
    <p><b>Example #1 Object oriented style</b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br /></span><span style="color: #FF8000">/*&nbsp;connect&nbsp;database&nbsp;test&nbsp;*/<br /></span><span style="color: #0000BB">$mysqli&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"my_user"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"my_password"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"test"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/*&nbsp;check&nbsp;connection&nbsp;*/<br /></span><span style="color: #007700">if&nbsp;(</span><span style="color: #0000BB">mysqli_connect_errno</span><span style="color: #007700">())&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Connect&nbsp;failed:&nbsp;%s\n"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">mysqli_connect_error</span><span style="color: #007700">());<br />&nbsp;&nbsp;&nbsp;&nbsp;exit();<br />}<br /><br /></span><span style="color: #FF8000">/*&nbsp;Set&nbsp;Variable&nbsp;a&nbsp;*/<br /></span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">query</span><span style="color: #007700">(</span><span style="color: #DD0000">"SET&nbsp;@a:=1"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/*&nbsp;reset&nbsp;all&nbsp;and&nbsp;select&nbsp;a&nbsp;new&nbsp;database&nbsp;*/<br /></span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">change_user</span><span style="color: #007700">(</span><span style="color: #DD0000">"my_user"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"my_password"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"world"</span><span style="color: #007700">);<br /><br />if&nbsp;(</span><span style="color: #0000BB">$result&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">query</span><span style="color: #007700">(</span><span style="color: #DD0000">"SELECT&nbsp;DATABASE()"</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$row&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$result</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">fetch_row</span><span style="color: #007700">();<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Default&nbsp;database:&nbsp;%s\n"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">]);<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$result</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">close</span><span style="color: #007700">();<br />}<br /><br />if&nbsp;(</span><span style="color: #0000BB">$result&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">query</span><span style="color: #007700">(</span><span style="color: #DD0000">"SELECT&nbsp;@a"</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$row&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$result</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">fetch_row</span><span style="color: #007700">();<br />&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(</span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">]&nbsp;===&nbsp;</span><span style="color: #0000BB">NULL</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Value&nbsp;of&nbsp;variable&nbsp;a&nbsp;is&nbsp;NULL\n"</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$result</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">close</span><span style="color: #007700">();<br />}<br /><br /></span><span style="color: #FF8000">/*&nbsp;close&nbsp;connection&nbsp;*/<br /></span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">close</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
   <div class="example">
    <p><b>Example #2 Procedural style</b></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #FF8000">/*&nbsp;connect&nbsp;database&nbsp;test&nbsp;*/<br /></span><span style="color: #0000BB">$link&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">mysqli_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"my_user"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"my_password"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"test"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/*&nbsp;check&nbsp;connection&nbsp;*/<br /></span><span style="color: #007700">if&nbsp;(!</span><span style="color: #0000BB">$link</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Connect&nbsp;failed:&nbsp;%s\n"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">mysqli_connect_error</span><span style="color: #007700">());<br />&nbsp;&nbsp;&nbsp;&nbsp;exit();<br />}<br /><br /></span><span style="color: #FF8000">/*&nbsp;Set&nbsp;Variable&nbsp;a&nbsp;*/<br /></span><span style="color: #0000BB">mysqli_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$link</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"SET&nbsp;@a:=1"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/*&nbsp;reset&nbsp;all&nbsp;and&nbsp;select&nbsp;a&nbsp;new&nbsp;database&nbsp;*/<br /></span><span style="color: #0000BB">mysqli_change_user</span><span style="color: #007700">(</span><span style="color: #0000BB">$link</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"my_user"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"my_password"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"world"</span><span style="color: #007700">);<br /><br />if&nbsp;(</span><span style="color: #0000BB">$result&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">mysqli_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$link</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"SELECT&nbsp;DATABASE()"</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$row&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">mysqli_fetch_row</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Default&nbsp;database:&nbsp;%s\n"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">]);<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">mysqli_free_result</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br />}<br /><br />if&nbsp;(</span><span style="color: #0000BB">$result&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">mysqli_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$link</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"SELECT&nbsp;@a"</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$row&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">mysqli_fetch_row</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(</span><span style="color: #0000BB">$row</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">]&nbsp;===&nbsp;</span><span style="color: #0000BB">NULL</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Value&nbsp;of&nbsp;variable&nbsp;a&nbsp;is&nbsp;NULL\n"</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">mysqli_free_result</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #FF8000">/*&nbsp;close&nbsp;connection&nbsp;*/<br /></span><span style="color: #0000BB">mysqli_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$link</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
   </div>

  </div>
  <p class="para">The above example will output:</p>
  <div class="example-contents"><pre>
<div class="cdata"><pre>
Default database: world
Value of variable a is NULL
</pre></div>
  </pre></div>
 </div>


 <div class="refsect1 seealso">
  <h3 class="title">See Also</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><a href="mysqli.connect.html" class="function" rel="rdfs-seeAlso">mysqli_connect()</a></li>
    <li class="member"><a href="mysqli.select-db.html" class="function" rel="rdfs-seeAlso">mysqli_select_db()</a></li>
   </ul>
  </p>
 </div>


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