1<!--$Id: txn_commit.so,v 10.49 2004/08/13 03:39:03 bostic Exp $--> 2<!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> 3<!--See the file LICENSE for redistribution information.--> 4<html> 5<head> 6<title>Berkeley DB: DbTxn::commit</title> 7<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit."> 8<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++"> 9</head> 10<body bgcolor=white> 11<table width="100%"><tr valign=top> 12<td> 13<b>DbTxn::commit</b> 14</td> 15<td align=right> 16<a href="/api_cxx/api_core.html"><img src="/images/api.gif" alt="API"></a> 17<a href="/ref/toc.html"><img src="/images/ref.gif" alt="Ref"></a></td> 18</tr></table> 19<hr size=1 noshade> 20<tt> 21<b><pre> 22#include <db_cxx.h> 23<p> 24int 25DbTxn::commit(u_int32_t flags); 26</pre></b> 27<hr size=1 noshade> 28<b>Description: DbTxn::commit</b> 29<p>The DbTxn::commit method ends the transaction.</p> 30<p>In the case of nested transactions, if the transaction is a parent 31transaction, committing the parent transaction causes all unresolved 32children of the parent to be committed. In the case of nested 33transactions, if the transaction is a child transaction, its locks are 34not released, but are acquired by its parent. Although the commit of the 35child transaction will succeed, the actual resolution of the child 36transaction is postponed until the parent transaction is committed or 37aborted; that is, if its parent transaction commits, it will be 38committed; and if its parent transaction aborts, it will be aborted.</p> 39<p>All cursors opened within the transaction must be closed before the 40transaction is committed.</p> 41<p>After DbTxn::commit has been called, regardless of its return, the 42<a href="/api_cxx/txn_class.html">DbTxn</a> handle may not be accessed again. If DbTxn::commit 43encounters an error, the transaction and all child transactions of the 44transaction are aborted.</p> 45<p>The DbTxn::commit method 46either returns a non-zero error value 47or throws an exception that encapsulates a non-zero error value on 48failure, and returns 0 on success. 49</p> 50<b>Parameters</b> <br> 51 <b>flags</b><ul compact><li>The <b>flags</b> parameter must be set to 0 or 52one of the following values: 53<br> 54<b><a name="DB_TXN_NOSYNC">DB_TXN_NOSYNC</a></b><ul compact><li>Do not synchronously flush the log. This means the transaction will 55exhibit the ACI (atomicity, consistency, and isolation) properties, but 56not D (durability); that is, database integrity will be maintained, but 57it is possible that this transaction may be undone during recovery. 58<p>This behavior may be set for a Berkeley DB environment using the 59<a href="/api_cxx/env_set_flags.html">DbEnv::set_flags</a> method or for a single transaction using the 60<a href="/api_cxx/txn_begin.html">DbEnv::txn_begin</a> method. Any value specified to this method overrides 61both of those settings.</p></ul> 62<b><a name="DB_TXN_SYNC">DB_TXN_SYNC</a></b><ul compact><li>Synchronously flush the log. This means the transaction will exhibit 63all of the ACID (atomicity, consistency, isolation, and durability) 64properties. 65<p>This behavior is the default for Berkeley DB environments unless the 66<a href="/api_cxx/env_set_flags.html#DB_TXN_NOSYNC">DB_TXN_NOSYNC</a> flag was specified to the 67<a href="/api_cxx/env_set_flags.html">DbEnv::set_flags</a> method. This behavior may also be set for a single 68transaction using the <a href="/api_cxx/txn_begin.html">DbEnv::txn_begin</a> method. Any value specified to this 69method overrides both of those settings.</p></ul> 70<br></ul> 71<br> 72<hr size=1 noshade> 73<br><b>Class</b> 74<a href="/api_cxx/env_class.html">DbEnv</a>, <a href="/api_cxx/txn_class.html">DbTxn</a> 75<br><b>See Also</b> 76<a href="/api_cxx/txn_list.html">Transaction Subsystem and Related Methods</a> 77</tt> 78<table width="100%"><tr><td><br></td><td align=right> 79<a href="/api_cxx/api_core.html"><img src="/images/api.gif" alt="API"></a><a href="/ref/toc.html"><img src="/images/ref.gif" alt="Ref"></a> 80</td></tr></table> 81<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font> 82</body> 83</html> 84
