1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"> 4 <head> 5 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 6 <title>Secondary Indices with Transaction Applications</title> 7 <link rel="stylesheet" href="gettingStarted.css" type="text/css" /> 8 <meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /> 9 <link rel="start" href="index.html" title="Getting Started with Berkeley DB Transaction Processing" /> 10 <link rel="up" href="usingtxns.html" title="Chapter 3. Transaction Basics" /> 11 <link rel="prev" href="txncursor.html" title="Transactional Cursors" /> 12 <link rel="next" href="maxtxns.html" title="Configuring the Transaction Subsystem" /> 13 </head> 14 <body> 15 <div class="navheader"> 16 <table width="100%" summary="Navigation header"> 17 <tr> 18 <th colspan="3" align="center">Secondary Indices with Transaction Applications</th> 19 </tr> 20 <tr> 21 <td width="20%" align="left"><a accesskey="p" href="txncursor.html">Prev</a> </td> 22 <th width="60%" align="center">Chapter 3. Transaction Basics</th> 23 <td width="20%" align="right"> <a accesskey="n" href="maxtxns.html">Next</a></td> 24 </tr> 25 </table> 26 <hr /> 27 </div> 28 <div class="sect1" lang="en" xml:lang="en"> 29 <div class="titlepage"> 30 <div> 31 <div> 32 <h2 class="title" style="clear: both"><a id="txnindices"></a>Secondary Indices with Transaction Applications</h2> 33 </div> 34 </div> 35 </div> 36 <p> 37 You can use transactions with your secondary indices so long as you 38 39 40 41 <span> 42 open the secondary index so that it is transactional. 43 </span> 44 45 46 </p> 47 <p> 48 All other aspects of using secondary indices with transactions are 49 identical to using secondary indices without transactions. In 50 addition, transaction-protecting 51 52 <span> 53 secondary cursors is performed just as you protect normal 54 cursors — you simply have to make sure the cursor is 55 opened using a transaction handle, and that the cursor is 56 closed before the handle is either either committed or 57 aborted. 58 </span> 59 See <a class="xref" href="txncursor.html" title="Transactional Cursors">Transactional Cursors</a> for details. 60 </p> 61 <p> 62 Note that when you use transactions to protect your database writes, your secondary indices are protected from 63 corruption because updates to the primary and the secondaries are performed in a single atomic transaction. 64 </p> 65 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> 66 <h3 class="title">Note</h3> 67 <p> 68 If you are using the DPL, then be aware that 69 you never have to provide a transactional 70 handle when opening an index, be it a primary 71 or a secondary. However, transactions are 72 enabled for your store, then all of the indexes 73 that you open will be enabled for transactional 74 usage. More, any write operation performed 75 using that index will be done using a 76 transaction, regardless of whether you 77 explictly provide a transactional handle to the 78 write operation. 79 </p> 80 <p> 81 If you do not explictly provide a transaction 82 handle to DPL write operations performed on a 83 transactional store, then auto commit is 84 silently used for that operation. 85 </p> 86 </div> 87 <p> 88 For example: 89 </p> 90 <pre class="programlisting">package db.GettingStarted; 91 92import com.sleepycat.bind.tuple.TupleBinding; 93import com.sleepycat.db.Database; 94import com.sleepycat.db.DatabaseType; 95import com.sleepycat.db.DatabaseConfig; 96import com.sleepycat.db.DatabaseException; 97import com.sleepycat.db.Environment; 98import com.sleepycat.db.EnvironmentConfig; 99import com.sleepycat.db.SecondaryDatabase; 100import com.sleepycat.db.SecondaryConfig; 101 102import java.io.FileNotFoundException; 103 104... 105 106// Environment and primary database opens omitted. 107 108SecondaryConfig mySecConfig = new SecondaryConfig(); 109mySecConfig.setAllowCreate(true); 110mySecConfig.setType(DatabaseType.BTREE); 111mySecConfig.setTransactional(true); 112 113SecondaryDatabase mySecDb = null; 114try { 115 // A fake tuple binding that is not actually implemented anywhere. 116 // The tuple binding is dependent on the data in use. 117 // See the Getting Started Guide for details 118 TupleBinding myTupleBinding = new MyTupleBinding(); 119 120 // Open the secondary. FullNameKeyCreator is not actually implemented 121 // anywhere. See the Getting Started Guide for details. 122 FullNameKeyCreator keyCreator = new FullNameKeyCreator(myTupleBinding); 123 124 // Set the key creator on the secondary config object. 125 mySecConfig.setKeyCreator(keyCreator); 126 127 // Perform the actual open. Because this database is configured to be 128 // transactional, the open is automatically wrapped in a transaction. 129 // - myEnv is the environment handle. 130 // - myDb is the primary database handle. 131 String secDbName = "mySecondaryDatabase"; 132 mySecDb = myEnv.openSecondary(null, secDbName, null, myDb, mySecConfig); 133} catch (DatabaseException de) { 134 // Exception handling goes here ... 135} catch (FileNotFoundException fnfe) { 136 // Exception handling goes here ... 137}</pre> 138 </div> 139 <div class="navfooter"> 140 <hr /> 141 <table width="100%" summary="Navigation footer"> 142 <tr> 143 <td width="40%" align="left"><a accesskey="p" href="txncursor.html">Prev</a> </td> 144 <td width="20%" align="center"> 145 <a accesskey="u" href="usingtxns.html">Up</a> 146 </td> 147 <td width="40%" align="right"> <a accesskey="n" href="maxtxns.html">Next</a></td> 148 </tr> 149 <tr> 150 <td width="40%" align="left" valign="top">Transactional Cursors </td> 151 <td width="20%" align="center"> 152 <a accesskey="h" href="index.html">Home</a> 153 </td> 154 <td width="40%" align="right" valign="top"> Configuring the Transaction Subsystem</td> 155 </tr> 156 </table> 157 </div> 158 </body> 159</html> 160