Sindbad~EG File Manager
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!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">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Why transactions?</title>
<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
<link rel="start" href="index.html" title="Berkeley DB Programmer's Reference Guide" />
<link rel="up" href="transapp.html" title="Chapter 11. Berkeley DB Transactional Data Store Applications" />
<link rel="prev" href="transapp.html" title="Chapter 11. Berkeley DB Transactional Data Store Applications" />
<link rel="next" href="transapp_term.html" title="Terminology" />
</head>
<body>
<div xmlns="" class="navheader">
<div class="libver">
<p>Library Version 18.1.40</p>
</div>
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">Why transactions?</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="transapp.html">Prev</a> </td>
<th width="60%" align="center">Chapter 11. Berkeley DB Transactional Data Store Applications </th>
<td width="20%" align="right"> <a accesskey="n" href="transapp_term.html">Next</a></td>
</tr>
</table>
<hr />
</div>
<div class="sect1" lang="en" xml:lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a id="transapp_why"></a>Why transactions?</h2>
</div>
</div>
</div>
<p>
Perhaps the first question to answer is "Why transactions?"
There are a number of reasons to include transactional support
in your applications. The most common ones are the
following:
</p>
<div class="variablelist">
<dl>
<dt>
<span class="term">Recoverability</span>
</dt>
<dd>
Applications often need to ensure that no matter
how the system or application fails, previously saved
data is available the next time the application runs.
This is often called Durability.
</dd>
<dt>
<span class="term">Atomicity</span>
</dt>
<dd>
Applications may need to make multiple changes
to one or more databases, but ensure that either all
of the changes happen, or none of them happens.
Transactions guarantee that a group of changes are
atomic; that is, if the application or system fails,
either all of the changes to the databases will appear
when the application next runs, or none of
them.
</dd>
<dt>
<span class="term">Isolation</span>
</dt>
<dd>
Applications may need to make changes in
isolation, that is, ensure that only a single thread
of control is modifying a key/data pair at a time.
Transactions ensure each thread of control sees all
records as if all other transactions either completed
before or after its transaction.
</dd>
</dl>
</div>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="transapp.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="transapp.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="transapp_term.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">Chapter 11. Berkeley DB Transactional Data Store Applications </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> Terminology</td>
</tr>
</table>
</div>
</body>
</html>
Sindbad File Manager Version 1.0, Coded By Sindbad EG ~ The Terrorists