diff options
Diffstat (limited to 'user_guide/database/transactions.html')
| -rw-r--r-- | user_guide/database/transactions.html | 398 |
1 files changed, 199 insertions, 199 deletions
diff --git a/user_guide/database/transactions.html b/user_guide/database/transactions.html index 8652aad18..1276cdc36 100644 --- a/user_guide/database/transactions.html +++ b/user_guide/database/transactions.html @@ -1,200 +1,200 @@ -<!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>Transactions : 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 1.7</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> ›
-Transactions
-</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>Transactions</h1>
-
-<p>CodeIgniter'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 than the more common MyISAM. Most other database platforms 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.
-</p>
-
-<h2>CodeIgniter's Approach to Transactions</h2>
-
-<p>CodeIgniter 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. This is particularly cumbersome with
-nested 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,
-but there's really no benefit).</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>$this->db->trans_complete();</kbd>
-</code>
-
-<p>You can run as many queries as you want between the start/complete functions and they will all be committed or rolled back based on success or failure
-of any given query.</p>
-
-
-<h2>Strict Mode</h2>
-
-<p>By default CodeIgniter runs all transactions in <dfn>Strict Mode</dfn>. When strict mode is enabled, if you are running multiple groups of
-transactions, if one group fails all groups will be rolled back. If strict mode is disabled, each group is treated independently, meaning
-a failure of one group will not affect any others.</p>
-
-<p>Strict Mode can be disabled as follows:</p>
-
-<code>$this->db->trans_strict(FALSE);</code>
-
-
-<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>$this->db->trans_status()</kbd> === FALSE)<br />
-{<br />
- // generate an error... or use the log_message() function to log your error<br />
-}
-</code>
-
-
-<h2>Enabling Transactions</h2>
-
-<p>Transactions are enabled automatically the moment you use <dfn>$this->db->trans_start()</dfn>. If you would like to disable transactions you
-can do so using <dfn>$this->db->trans_off()</dfn>:</p>
-
-<code>
-<kbd>$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>:</p>
-
-<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="fields.html">Field MetaData</a> ·
-<a href="#top">Top of Page</a> ·
-<a href="../index.html">User Guide Home</a> ·
-Next Topic: <a href="table_data.html">Table Metadata</a>
-</p>
-<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006-2008 · <a href="http://ellislab.com/">Ellislab, Inc.</a></p>
-</div>
-
-</body>
+<!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>Transactions : 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 1.7</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> › +Transactions +</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>Transactions</h1> + +<p>CodeIgniter'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 than the more common MyISAM. Most other database platforms 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. +</p> + +<h2>CodeIgniter's Approach to Transactions</h2> + +<p>CodeIgniter 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. This is particularly cumbersome with +nested 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, +but there's really no benefit).</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 +of any given query.</p> + + +<h2>Strict Mode</h2> + +<p>By default CodeIgniter runs all transactions in <dfn>Strict Mode</dfn>. When strict mode is enabled, if you are running multiple groups of +transactions, if one group fails all groups will be rolled back. If strict mode is disabled, each group is treated independently, meaning +a failure of one group will not affect any others.</p> + +<p>Strict Mode can be disabled as follows:</p> + +<code>$this->db->trans_strict(FALSE);</code> + + +<h2>Managing Errors</h2> + +<p>If you have error reporting enabled in your <dfn>config/database.php</dfn> file you'll see a standard error message if the commit was unsuccessful. If debugging is turned off, you can +manage your own errors like this:</p> + +<code> +$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... or use the log_message() function to log your 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>:</p> + +<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>$this->db->trans_start()</dfn> function to <samp>TRUE</samp>:</p> + +<code> +$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="fields.html">Field MetaData</a> · +<a href="#top">Top of Page</a> · +<a href="../index.html">User Guide Home</a> · +Next Topic: <a href="table_data.html">Table Metadata</a> +</p> +<p><a href="http://codeigniter.com">CodeIgniter</a> · Copyright © 2006-2008 · <a href="http://ellislab.com/">Ellislab, Inc.</a></p> +</div> + +</body> </html>
\ No newline at end of file |