<?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>Secondary Indices with Transaction Applications</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="txncursor.html" title="Transactional Cursors" /> <link rel="next" href="maxtxns.html" title="Configuring the Transaction Subsystem" /> </head> <body> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr> <th colspan="3" align="center">Secondary Indices with Transaction Applications</th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="txncursor.html">Prev</a> </td> <th width="60%" align="center">Chapter 3. Transaction Basics</th> <td width="20%" align="right"> <a accesskey="n" href="maxtxns.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="txnindices"></a>Secondary Indices with Transaction Applications</h2> </div> </div> <div></div> </div> <p> You can use transactions with your secondary indices so long as you <span> open the secondary index so that it is transactional. </span> </p> <p> All other aspects of using secondary indices with transactions are identical to using secondary indices without transactions. In addition, transaction-protecting <span> secondary cursors is performed just as you protect normal cursors — you simply have to make sure the cursor is opened using a transaction handle, and that the cursor is closed before the handle is either either committed or aborted. </span> See <a href="txncursor.html">Transactional Cursors</a> for details. </p> <p> Note that when you use transactions to protect your database writes, your secondary indices are protected from corruption because updates to the primary and the secondaries are performed in a single atomic transaction. </p> <p> For example: </p> <pre class="programlisting">package db.GettingStarted; import com.sleepycat.bind.tuple.TupleBinding; import com.sleepycat.db.Database; import com.sleepycat.db.DatabaseType; import com.sleepycat.db.DatabaseConfig; import com.sleepycat.db.DatabaseException; import com.sleepycat.db.Environment; import com.sleepycat.db.EnvironmentConfig; import com.sleepycat.db.SecondaryDatabase; import com.sleepycat.db.SecondaryConfig; import java.io.FileNotFoundException; ... // Environment and primary database opens omitted. SecondaryConfig mySecConfig = new SecondaryConfig(); mySecConfig.setAllowCreate(true); mySecConfig.setType(DatabaseType.BTREE); mySecConfig.setTransactional(true); SecondaryDatabase mySecDb = null; try { // A fake tuple binding that is not actually implemented anywhere. // The tuple binding is dependent on the data in use. // See the Getting Started Guide for details TupleBinding myTupleBinding = new MyTupleBinding(); // Open the secondary. FullNameKeyCreator is not actually implemented // anywhere. See the Getting Started Guide for details. FullNameKeyCreator keyCreator = new FullNameKeyCreator(myTupleBinding); // Set the key creator on the secondary config object. mySecConfig.setKeyCreator(keyCreator); // Perform the actual open. Because this database is configured to be // transactional, the open is automatically wrapped in a transaction. // - myEnv is the environment handle. // - myDb is the primary database handle. String secDbName = "mySecondaryDatabase"; mySecDb = myEnv.openSecondary(null, secDbName, null, myDb, mySecConfig); } catch (DatabaseException de) { // Exception handling goes here ... } catch (FileNotFoundException fnfe) { // 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="txncursor.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="maxtxns.html">Next</a></td> </tr> <tr> <td width="40%" align="left" valign="top">Transactional Cursors </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> <td width="40%" align="right" valign="top"> Configuring the Transaction Subsystem</td> </tr> </table> </div> </body> </html>