| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> |
| <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> |
| <head> |
| |
| <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> |
| <title>Queries : CodeIgniter User Guide</title> |
| |
| <style type='text/css' media='all'>@import url('../userguide.css');</style> |
| <link rel='stylesheet' type='text/css' media='all' href='../userguide.css' /> |
| |
| <script type="text/javascript" src="../nav/nav.js"></script> |
| <script type="text/javascript" src="../nav/prototype.lite.js"></script> |
| <script type="text/javascript" src="../nav/moo.fx.js"></script> |
| <script type="text/javascript" src="../nav/user_guide_menu.js"></script> |
| |
| <meta http-equiv='expires' content='-1' /> |
| <meta http-equiv= 'pragma' content='no-cache' /> |
| <meta name='robots' content='all' /> |
| <meta name='author' content='ExpressionEngine Dev Team' /> |
| <meta name='description' content='CodeIgniter User Guide' /> |
| |
| </head> |
| <body> |
| |
| <!-- START NAVIGATION --> |
| <div id="nav"><div id="nav_inner"><script type="text/javascript">create_menu('../');</script></div></div> |
| <div id="nav2"><a name="top"></a><a href="javascript:void(0);" onclick="myHeight.toggle();"><img src="../images/nav_toggle_darker.jpg" width="154" height="43" border="0" title="Toggle Table of Contents" alt="Toggle Table of Contents" /></a></div> |
| <div id="masthead"> |
| <table cellpadding="0" cellspacing="0" border="0" style="width:100%"> |
| <tr> |
| <td><h1>CodeIgniter User Guide Version 2.0.0</h1></td> |
| <td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td> |
| </tr> |
| </table> |
| </div> |
| <!-- END NAVIGATION --> |
| |
| |
| <!-- START BREADCRUMB --> |
| <table cellpadding="0" cellspacing="0" border="0" style="width:100%"> |
| <tr> |
| <td id="breadcrumb"> |
| <a href="http://codeigniter.com/">CodeIgniter Home</a> › |
| <a href="../index.html">User Guide Home</a> › |
| <a href="index.html">Database Library</a> › |
| Queries |
| </td> |
| <td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" /> <input type="submit" class="submit" name="sa" value="Go" /></form></td> |
| </tr> |
| </table> |
| <!-- END BREADCRUMB --> |
| |
| |
| |
| <br clear="all" /> |
| |
| |
| <!-- START CONTENT --> |
| <div id="content"> |
| |
| |
| <h1>Queries</h1> |
| |
| <h2>$this->db->query();</h2> |
| |
| <p>To submit a query, use the following function:</p> |
| |
| <code>$this->db->query('YOUR QUERY HERE');</code> |
| |
| <p>The <dfn>query()</dfn> function returns a database result <strong>object</strong> when "read" type queries are run, |
| which you can use to <a href="results.html">show your results</a>. When "write" type queries are run it simply returns TRUE or FALSE |
| depending on success or failure. When retrieving data you will typically assign the query to your own variable, like this:</p> |
| |
| <code><var>$query</var> = $this->db->query('YOUR QUERY HERE');</code> |
| |
| <h2>$this->db->simple_query();</h2> |
| |
| <p>This is a simplified version of the <dfn>$this->db->query()</dfn> function. It ONLY returns TRUE/FALSE on success or failure. |
| It DOES NOT return a database result set, nor does it set the query timer, or compile bind data, or store your query for debugging. |
| It simply lets you submit a query. Most users will rarely use this function.</p> |
| |
| |
| <h1>Adding Database prefixes manually</h1> |
| <p>If you have configured a database prefix and would like to add it in manually for, you can use the following.</p> |
| <p><code>$this->db->dbprefix('tablename');<br /> |
| // outputs prefix_tablename</code></p> |
| |
| |
| <h1>Protecting identifiers</h1> |
| <p>In many databases it is advisable to protect table and field names - for example with backticks in MySQL. <strong>Active Record queries are automatically protected</strong>, however if you need to manually protect an identifier you can use:</p> |
| <p><code>$this->db->protect_identifiers('table_name');</code></p> |
| |
| <p>This function will also add a table prefix to your table, assuming you have a prefix specified in your database config file. To enable the prefixing set <kbd>TRUE</kbd> (boolen) via the second parameter:</p> |
| <p><code>$this->db->protect_identifiers('table_name', <kbd>TRUE</kbd>);</code></p> |
| |
| |
| <h1>Escaping Queries</h1> |
| <p>It's a very good security practice to escape your data before submitting it into your database. |
| CodeIgniter has three methods that help you do this:</p> |
| |
| <ol> |
| <li><strong>$this->db->escape()</strong> This function determines the data type so that it |
| can escape only string data. It also automatically adds single quotes around the data so you don't have to: |
| |
| <code>$sql = "INSERT INTO table (title) VALUES(".$this->db->escape($title).")";</code></li> |
| |
| <li><strong>$this->db->escape_str()</strong> This function escapes the data passed to it, regardless of type. |
| Most of the time you'll use the above function rather than this one. Use the function like this: |
| |
| <code>$sql = "INSERT INTO table (title) VALUES('".$this->db->escape_str($title)."')";</code></li> |
| |
| <li><strong>$this->db->escape_like_str()</strong> This method should be used when strings are to be used in LIKE |
| conditions so that LIKE wildcards ('%', '_') in the string are also properly escaped. |
| |
| <code>$search = '20% raise';<br /> |
| $sql = "SELECT id FROM table WHERE column LIKE '%".$this->db->escape_like_str($search)."%'";</code></li> |
| |
| </ol> |
| |
| |
| <h1>Query Bindings</h1> |
| |
| |
| <p>Bindings enable you to simplify your query syntax by letting the system put the queries together for you. Consider the following example:</p> |
| |
| <code> |
| $sql = "SELECT * FROM some_table WHERE id = <var>?</var> AND status = <var>?</var> AND author = <var>?</var>"; |
| <br /><br /> |
| $this->db->query($sql, array(3, 'live', 'Rick')); |
| </code> |
| |
| <p>The question marks in the query are automatically replaced with the values in the array in the second parameter of the query function.</p> |
| <p class="important">The secondary benefit of using binds is that the values are automatically escaped, producing safer queries. You don't have to remember to manually escape data; the engine does it automatically for you.</p> |
| |
| |
| |
| </div> |
| <!-- END CONTENT --> |
| |
| |
| <div id="footer"> |
| <p> |
| Previous Topic: <a href="connecting.html">Connecting to your Database</a> |
| · |
| <a href="#top">Top of Page</a> · |
| <a href="../index.html">User Guide Home</a> · |
| Next Topic: <a href="results.html">Query Results</a> |
| </p> |
| <p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006-2010 · <a href="http://ellislab.com/">EllisLab, Inc.</a></p> |
| </div> |
| |
| </body> |
| </html> |