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<h1>数据库快速入门例子代码</h1>

<p>下面的内容将简单说明怎样使用数据库。更详细的信息请阅读各个函数的单独介绍页面。</p>


<h2>初始化数据库类</h2>

<p>下面的代码将依据你的<a href="configuration.html">数据库配置</a>载入并初始化数据库类:</p>

<code>$this->load->database();</code>

<p>一旦被载入，你可以在任何地方像这样使用它：</p>

<p>注意: 如果你的所有页面均要求初始化数据库类，你可以让它自动加载。详见 <a href="connecting.html">数据库连接</a>。</p>


<h2>多结果标准查询（对象形式）</h2>

<code>$query = $this->db->query('SELECT name, title, email FROM my_table');<br />
<br />
foreach ($query->result() as $row)<br />
&#123;<br />
&nbsp;&nbsp;&nbsp;&nbsp;echo $row->title;<br />
&nbsp;&nbsp;&nbsp;&nbsp;echo $row->name;<br />
&nbsp;&nbsp;&nbsp;&nbsp;echo $row->email;<br />

&#125;<br />
<br />
echo 'Total Results: ' . $query->num_rows();
</code>

<p>上面的<dfn>result()</dfn>函数返回一个<strong>对象</strong>的数组。例如：$row->title</p>


<h2>多结果标准查询（数组形式）</h2>

<code>$query = $this->db->query('SELECT name, title, email FROM my_table');<br />
<br />
foreach ($query->result_array() as $row)<br />
&#123;<br />
&nbsp;&nbsp;&nbsp;&nbsp;echo $row['title'];<br />
&nbsp;&nbsp;&nbsp;&nbsp;echo $row['name'];<br />
&nbsp;&nbsp;&nbsp;&nbsp;echo $row['email'];<br />
&#125;</code>

<p>上面的<dfn>result_array()</dfn>函数返回一个带下标的数组。例如：$row['title']</p>


<h2>测试查询结果</h2>

<p>如果你的查询可能不返回结果，我们建议你先使用 <dfn>num_rows()</dfn>函数来测试:</p>

<code>
$query = $this->db->query("YOUR QUERY");<br />
<br />
if ($query->num_rows() > 0)<br />
&#123;<br />
&nbsp;&nbsp;&nbsp;foreach ($query->result() as $row)<br />
&nbsp;&nbsp;&nbsp;&#123;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo $row->title;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo $row->name;<br />

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo $row->body;<br />
&nbsp;&nbsp;&nbsp;&#125;<br />
&#125;
</code>


<h2>单结果标准查询（对象形式）</h2>

<code>$query = $this->db->query('SELECT name FROM my_table LIMIT 1');<br />
<br />
$row = $query->row();<br />

echo $row->name;<br />
</code>

<p>上面的<dfn>row()</dfn>函数返回一个 <strong>对象</strong>。例如：$row->name</p>


<h2>单结果标准查询（数组形式）</h2>

<code>$query = $this->db->query('SELECT name FROM my_table LIMIT 1');<br />

<br />
$row = $query->row_array();<br />
echo $row['name'];<br />
</code>

<p>上面的<dfn>row_array()</dfn>函数返回一个 <strong>数组</strong>。例如：$row['name']</p>


<h2>标准插入(insert)</h2>

<code>
$sql = "INSERT INTO mytable (title, name) <br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;VALUES (".$this->db->escape($title).", ".$this->db->escape($name).")";<br />
<br />
$this->db->query($sql);<br />
<br />
echo $this->db->affected_rows();
</code>


<h2>快捷查询</h2>

<p><a href="active_record.html">快捷查询类</a>能为我们提供快速取得数据的途径:</p>

<code>
$query = $this->db->get('table_name');<br />
<br />
foreach ($query->result() as $row)<br />
&#123;<br />
&nbsp;&nbsp;&nbsp;&nbsp;echo $row->title;<br />

&#125;</code>

<p>上面的<dfn>get()</dfn>函数返回数据表中所有的结果。
<a href="active_record.html">快捷查询类</a> 提供所有数据库操作的快捷函数。</p>


<h2>快捷插入(insert)</h2>

<code>

$data = array(<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'title' => $title,<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'name' => $name,<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'date' => $date<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;);<br />
<br />
$this->db->insert('mytable', $data);
<br /><br />
// Produces: INSERT INTO mytable (title, name, date) VALUES ('&#123;$title&#125;', '&#123;$name&#125;', '&#123;$date&#125;')</code><p>&nbsp;</p>
<div id="Contributors">
翻译贡献者:
gaochao, Hex, longbill</div>
<div id="DocDate">
最后修改: 2008-01-02 20:21:50</div>
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