diff options
| author | admin <devnull@localhost> | 2006-09-24 19:59:33 +0200 |
|---|---|---|
| committer | admin <devnull@localhost> | 2006-09-24 19:59:33 +0200 |
| commit | fb28bb8d3bb01993e83126be028a1dda43422a39 (patch) | |
| tree | 874dda70bb048a55fa2783a1f1e3cfeea66f26f7 /user_guide/database/transactions.html | |
| parent | 5808346898ec9c602893fc54540958a8c556be29 (diff) | |
Adding database folder
Diffstat (limited to 'user_guide/database/transactions.html')
| -rw-r--r-- | user_guide/database/transactions.html | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/user_guide/database/transactions.html b/user_guide/database/transactions.html new file mode 100644 index 000000000..649e4081f --- /dev/null +++ b/user_guide/database/transactions.html @@ -0,0 +1,196 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html>
+<head>
+
+<title>Code Igniter 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' />
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+}
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+<meta name='author' content='Rick Ellis' />
+<meta name='description' content='Code Igniter 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.jpg" width="153" height="44" 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>Code Igniter User Guide Version 1.4.1</h1></td>
+<td id="breadcrumb_right"><a href="../toc.html">Full Table of Contents</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://www.codeigniter.com/">Code Igniter Home</a> ›
+<a href="../index.html">User Guide Home</a> ›
+<a href="index.html">Database Library</a> ›
+Transactions
+</td>
+<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="www.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>Transactions</h1>
+
+<p>Code Igniter's database abstraction allows you to use <dfn>transactions</dfn> with databases that support transaction-safe table types. In MySQL, you'll need
+to be running InnoDB or BDB table types rather then the more common MyISAM. Most other databases support transactions natively.</p>
+
+<p>If you are not familiar with
+transactions we recommend you find a good online resource to learn about them for your particular database. The information below assumes you
+have a basic understanding of transactions. For most sites, however, transactions won't be necessary.
+</p>
+
+<h2>Code Igniter's Approach to Transactions</h2>
+
+<p>Code Igniter utilizes an approach to transactions that is very similar to the process used by the popular database class ADODB. We've chosen that approach
+because it greatly simplifies the process of running transactions. In most cases all that is required are two lines of code.</p>
+
+<p>Traditionally transactions have required a fair amount of work to implement since they demand that you to keep track of your queries
+and determine whether to <dfn>commit</dfn> or <dfn>rollback</dfn> based on the success or failure of your queries. In contrast,
+we've implemented a smart transaction system that does all this for you automatically (you can also manage your transactions manually if you choose to).</p>
+
+<h2>Running Transactions</h2>
+
+<p>To run your queries using transactions you will use the <dfn>$this->db->trans_start()</dfn> and <dfn>$this->db->trans_complete()</dfn> functions as follows:</p>
+
+<code>
+<kbd>$this->db->trans_start();</kbd><br />
+$this->db->query('AN SQL QUERY...');<br />
+$this->db->query('ANOTHER QUERY...');<br />
+$this->db->query('AND YET ANOTHER QUERY...');<br />
+<kbd>$this->db->trans_complete();</kbd>
+</code>
+
+<p>You can run as many queries as you want between the start/complete functions and they will all be committed or rolled back based on success or failure.</p>
+
+
+<h2>Managing Errors</h2>
+
+<p>If you have error reporting enabled in your <dfn>config/database.php</dfn> file you'll see a standard error message if the commit was unsuccessful. If debugging is turned off, you can
+manage your own errors like this:</p>
+
+<code>
+$this->db->trans_start();<br />
+$this->db->query('AN SQL QUERY...');<br />
+$this->db->query('ANOTHER QUERY...');<br />
+$this->db->trans_complete();<br />
+<br />
+if (<kbd>$this->db->trans_status()</kbd> === FALSE)<br />
+{<br />
+ // generate an error....<br />
+}
+</code>
+
+
+<h2>Enabling Transactions</h2>
+
+<p>Transactions are enabled automatically the moment you use <dfn>$this->db->trans_start()</dfn>. If you would like to disable transactions you
+can do so using <dfn>$this->db->trans_off()</dfn>:
+
+<code>
+<kbd>$this->db->trans_off()</kbd><br /><br />
+
+$this->db->trans_start();<br />
+$this->db->query('AN SQL QUERY...');<br />
+$this->db->trans_complete();
+</code>
+
+<p class="important">When transactions are disabled, your queries will be auto-commited, just as they are when running queries without transactions.</p>
+
+
+<h2>Test Mode</h2>
+
+<p>You can optionally put the transaction system into "test mode", which will cause your queries to be rolled back -- even if the queries produce a valid result.
+To use test mode simply set the first parameter in the <dfn>$this->db->trans_start()</dfn> function to <samp>TRUE</samp>:
+
+<code>
+$this->db->trans_start(<samp>TRUE</samp>); // Query will be rolled back<br />
+$this->db->query('AN SQL QUERY...');<br />
+$this->db->trans_complete();
+</code>
+
+
+<h2>Running Transactions Manually</h2>
+
+<p>If you would like to run transactions manually you can do so as follows:</p>
+
+<code>
+$this->db->trans_begin();<br /><br />
+
+$this->db->query('AN SQL QUERY...');<br />
+$this->db->query('ANOTHER QUERY...');<br />
+$this->db->query('AND YET ANOTHER QUERY...');<br />
+
+<br />
+
+if ($this->db->trans_status() === FALSE)<br />
+{<br />
+ $this->db->trans_rollback();<br />
+}<br />
+else<br />
+{<br />
+ $this->db->trans_commit();<br />
+}<br />
+</code>
+
+<p class="important"><strong>Note:</strong> Make sure to use <kbd>$this->db->trans_begin()</kbd> when running manual transactions, <strong>NOT</strong>
+<dfn>$this->db->trans_start()</dfn>.</p>
+
+
+
+
+
+
+
+
+</div>
+<!-- END CONTENT -->
+
+
+<div id="footer">
+<p>
+Previous Topic: <a href="index.html">Database Class</a>
+ ·
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+<p>
+<p><a href="http://www.codeigniter.com">Code Igniter</a> · Copyright © 2006 · <a href="http://www.pmachine.com">pMachine, Inc.</a></p>
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+
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+</html>
\ No newline at end of file |