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Query Results
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<h1>Generating Query Results</h1>
<p>There are several ways to generate query results:</p>
<h2>result()</h2>
<p>This function returns the query result as an array of <strong>objects</strong>, or <strong>an empty array</strong> on failure.
Typically you'll use this in a foreach loop, like this:</p>
<code>
$query = $this->db->query("YOUR QUERY");<br />
<br />
foreach ($query->result() as $row)<br />
{<br />
echo $row->title;<br />
echo $row->name;<br />
echo $row->body;<br />
}</code>
<p>The above <dfn>function</dfn> is an alias of <dfn>result_object()</dfn>.</p>
<p>If you run queries that might <strong>not</strong> produce a result, you are encouraged to test the result first:</p>
<code>
$query = $this->db->query("YOUR QUERY");<br />
<br />
if ($query->num_rows() > 0)<br />
{<br />
foreach ($query->result() as $row)<br />
{<br />
echo $row->title;<br />
echo $row->name;<br />
echo $row->body;<br />
}<br />
}
</code>
<p>You can also pass a string to result() which represents a class to instantiate for each result object (note: this class must be loaded)</p>
<code>
$query = $this->db->query("SELECT * FROM users;");<br />
<br />
foreach ($query->result('User') as $row)<br />
{<br />
echo $row->name; // call attributes<br />
echo $row->reverse_name(); // or methods defined on the 'User' class<br />
}
</code>
<h2>result_array()</h2>
<p>This function returns the query result as a pure array, or an empty array when no result is produced. Typically you'll use this in a foreach loop, like this:</p>
<code>
$query = $this->db->query("YOUR QUERY");<br />
<br />
foreach ($query->result_array() as $row)<br />
{<br />
echo $row['title'];<br />
echo $row['name'];<br />
echo $row['body'];<br />
}</code>
<h2>row()</h2>
<p>This function returns a single result row. If your query has more than one row, it returns only the first row.
The result is returned as an <strong>object</strong>. Here's a usage example:</p>
<code>
$query = $this->db->query("YOUR QUERY");<br />
<br />
if ($query->num_rows() > 0)<br />
{<br />
$row = $query->row();
<br /><br />
echo $row->title;<br />
echo $row->name;<br />
echo $row->body;<br />
}
</code>
<p>If you want a specific row returned you can submit the row number as a digit in the first parameter:</p>
<code>$row = $query->row(<dfn>5</dfn>);</code>
<p>You can also add a second String parameter, which is the name of a class to instantiate the row with:</p>
<code>
$query = $this->db->query("SELECT * FROM users LIMIT 1;");<br />
<br />
$query->row(0, 'User')<br />
echo $row->name; // call attributes<br />
echo $row->reverse_name(); // or methods defined on the 'User' class<br />
</code>
<h2>row_array()</h2>
<p>Identical to the above <var>row()</var> function, except it returns an array. Example:</p>
<code>
$query = $this->db->query("YOUR QUERY");<br />
<br />
if ($query->num_rows() > 0)<br />
{<br />
$row = $query->row_array();
<br /><br />
echo $row['title'];<br />
echo $row['name'];<br />
echo $row['body'];<br />
}
</code>
<p>If you want a specific row returned you can submit the row number as a digit in the first parameter:</p>
<code>$row = $query->row_array(<dfn>5</dfn>);</code>
<p>In addition, you can walk forward/backwards/first/last through your results using these variations:</p>
<p>
<strong>$row = $query->first_row()</strong><br />
<strong>$row = $query->last_row()</strong><br />
<strong>$row = $query->next_row()</strong><br />
<strong>$row = $query->previous_row()</strong>
</p>
<p>By default they return an object unless you put the word "array" in the parameter:</p>
<p>
<strong>$row = $query->first_row('array')</strong><br />
<strong>$row = $query->last_row('array')</strong><br />
<strong>$row = $query->next_row('array')</strong><br />
<strong>$row = $query->previous_row('array')</strong>
</p>
<h1>Result Helper Functions</h1>
<h2>$query->num_rows()</h2>
<p>The number of rows returned by the query. Note: In this example, <dfn>$query</dfn> is the variable that the query result object is assigned to:</p>
<code>$query = $this->db->query('SELECT * FROM my_table');<br /><br />
echo $query->num_rows();
</code>
<h2>$query->num_fields()</h2>
<p>The number of FIELDS (columns) returned by the query. Make sure to call the function using your query result object:</p>
<code>$query = $this->db->query('SELECT * FROM my_table');<br /><br />
echo $query->num_fields();
</code>
<h2>$query->free_result()</h2>
<p>It frees the memory associated with the result and deletes the result resource ID. Normally PHP frees its memory automatically at the end of script
execution. However, if you are running a lot of queries in a particular script you might want to free the result after each query result has been
generated in order to cut down on memory consumptions. Example:
</p>
<code>$query = $this->db->query('SELECT title FROM my_table');<br /><br />
foreach ($query->result() as $row)<br />
{<br />
echo $row->title;<br />
}<br />
$query->free_result(); // The $query result object will no longer be available<br />
<br />
$query2 = $this->db->query('SELECT name FROM some_table');<br /><br />
$row = $query2->row();<br />
echo $row->name;<br />
$query2->free_result(); // The $query2 result object will no longer be available
</code>
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