<?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>Auto Commit</title> <link rel="stylesheet" href="gettingStarted.css" type="text/css" /> <meta name="generator" content="DocBook XSL Stylesheets V1.62.4" /> <link rel="home" href="index.html" title="Getting Started with Berkeley DB Transaction Processing" /> <link rel="up" href="usingtxns.html" title="Chapter 3. Transaction Basics" /> <link rel="previous" href="abortresults.html" title="Aborting a Transaction" /> <link rel="next" href="nestedtxn.html" title="Nested Transactions" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">Auto Commit</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="abortresults.html">Prev</a> </td> <th width="60%" align="center">Chapter 3. Transaction Basics</th> <td width="20%" align="right"> <a accesskey="n" href="nestedtxn.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="autocommit"></a>Auto Commit</h2> </div> </div> <div></div> </div> <p> While transactions are frequently used to provide atomicity to multiple database <span> or store </span> operations, it is sometimes necessary to perform a single database <span> or store </span> operation under the control of a transaction. Rather than force you to obtain a transaction, perform the single write operation, and then either commit or abort the transaction, you can automatically group this sequence of events using <span class="emphasis"><em>auto commit</em></span>. </p> <p> To use auto commit: </p> <div class="orderedlist"> <ol type="1"> <li> <p> Open your environment and your databases <span> or store </span> so that they support transactions. See <a href="enabletxn.html">Enabling Transactions</a> for details. </p> </li> <li> <p> Do not provide a transactional handle to the method that is performing the database <span> or store </span> write operation. </p> </li> </ol> </div> <p> Note that auto commit is not available for cursors. You must always open your cursor using a transaction if you want the cursor's operations to be transactional protected. See <a href="txncursor.html">Transactional Cursors</a> for details on using transactional cursors. </p> <p> For example, the following uses auto commit to perform the database write operation: </p> <pre class="programlisting">package db.txn; import com.sleepycat.db.Database; import com.sleepycat.db.DatabaseConfig; import com.sleepycat.db.DatabaseEntry; import com.sleepycat.db.DatabaseException; import com.sleepycat.db.Environment; import com.sleepycat.db.EnvironmentConfig; import java.io.File; ... Database myDatabase = null; Environment myEnv = null; try { EnvironmentConfig myEnvConfig = new EnvironmentConfig(); myEnvConfig.setInitializeCache(true); myEnvConfig.setInitializeLocking(true); myEnvConfig.setInitializeLogging(true); myEnvConfig.setTransactional(true); myEnv = new Environment(new File("/my/env/home"), myEnvConfig); // Open the database. DatabaseConfig dbConfig = new DatabaseConfig(); dbConfig.setTransactional(true); dbConfig.setType(DatabaseType.BTREE); myDatabase = myEnv.openDatabase(null, // txn handle "sampleDatabase", // db file name null, // db name dbConfig); String keyString = "thekey"; String dataString = "thedata"; DatabaseEntry key = new DatabaseEntry(keyString.getBytes("UTF-8")); DatabaseEntry data = new DatabaseEntry(dataString.getBytes("UTF-8")); // Perform the write. Because the database was opened to // support transactions, this write is performed using auto commit. myDatabase.put(null, key, data); } catch (DatabaseException de) { // Exception handling goes here } </pre> </div> <div class="navfooter"> <hr /> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"><a accesskey="p" href="abortresults.html">Prev</a> </td> <td width="20%" align="center"> <a accesskey="u" href="usingtxns.html">Up</a> </td> <td width="40%" align="right"> <a accesskey="n" href="nestedtxn.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">Aborting a Transaction </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> Nested Transactions</td> </tr> </table> </div> </body> </html>