1<!--$Id: env_dbremove.so,v 10.49 2004/12/16 19:13:01 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: DbEnv::dbremove</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>DbEnv::dbremove</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 25DbEnv::dbremove(DbTxn *txnid, 26 const char *file, const char *database, u_int32_t flags); 27</pre></b> 28<hr size=1 noshade> 29<b>Description: DbEnv::dbremove</b> 30<p>The DbEnv::dbremove method removes the database specified by the 31<b>file</b> and <b>database</b> parameters. If no <b>database</b> 32is specified, the underlying file represented by <b>file</b> is 33removed, incidentally removing all of the databases it contained.</p> 34<p>Applications should never remove databases with open <a href="../api_cxx/db_class.html">Db</a> handles, 35or in the case of removing a file, when any database in the file has an 36open handle. For example, some architectures do not permit the removal 37of files with open system handles. On these architectures, attempts to 38remove databases currently in use by any thread of control in the system 39may fail.</p> 40<p>The DbEnv::dbremove method 41either returns a non-zero error value 42or throws an exception that encapsulates a non-zero error value on 43failure, and returns 0 on success. 44</p> 45<b>Parameters</b> <br> 46 <b>database</b><ul compact><li>The <b>database</b> parameter is the database to be removed.</ul> 47 <b>file</b><ul compact><li>The <b>file</b> parameter is the physical file which contains the 48database(s) to be removed.</ul> 49<p>When using a Unicode build on Windows (the default), the <b>file</b> 50argument will be interpreted as a UTF-8 string, which is equivalent to 51ASCII for Latin characters.</p> 52 <b>flags</b><ul compact><li>The <b>flags</b> parameter must be set to 0 or 53the following value: 54<br> 55<b><a name="DB_AUTO_COMMIT">DB_AUTO_COMMIT</a></b><ul compact><li>Enclose the DbEnv::dbremove call within a transaction. If the call succeeds, 56changes made by the operation will be recoverable. If the call fails, 57the operation will have made no changes.</ul> 58<br></ul> 59 <b>txnid</b><ul compact><li>If the operation is part of an application-specified transaction, the 60<b>txnid</b> parameter is a transaction handle returned from 61<a href="../api_cxx/txn_begin.html">DbEnv::txn_begin</a>; if the operation is part of a Berkeley DB Concurrent Data Store group, the 62<b>txnid</b> parameter is a handle returned from 63<a href="../api_cxx/env_cdsgroup_begin.html">DbEnv::cdsgroup_begin</a>; otherwise NULL. 64If no transaction handle is 65specified, but the 66DB_AUTO_COMMIT flag is specified, 67the operation will be implicitly transaction protected. 68</ul> 69<br> 70<br><b>Environment Variables</b> 71<p>The 72environment variable <b>DB_HOME</b> may be used as the path of the 73database environment home.</p> 74<p>DbEnv::dbremove is affected by any database directory specified using 75the <a href="../api_cxx/env_set_data_dir.html">DbEnv::set_data_dir</a> method, or by setting the "set_data_dir" string 76in the environment's <a href="../ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> file.</p> 77<br><b>Errors</b> 78<p>The DbEnv::dbremove method 79may fail and throw 80<a href="../api_cxx/except_class.html">DbException</a>, 81encapsulating one of the following non-zero errors, or return one of 82the following non-zero errors:</p> 83<br> 84<b>EINVAL</b><ul compact><li>If DbEnv::dbremove called before <a href="../api_cxx/env_open.html">DbEnv::open</a> was called; or if an 85invalid flag value or parameter was specified.</ul> 86<br> 87<br> 88<b>ENOENT</b><ul compact><li>The file or directory does not exist.</ul> 89<br> 90<p>If a transactional database environment operation was selected to 91resolve a deadlock, the DbEnv::dbremove method will fail and 92either return <a href="../ref/program/errorret.html#DB_LOCK_DEADLOCK">DB_LOCK_DEADLOCK</a> or 93throw a <a href="../api_cxx/deadlock_class.html">DbDeadlockException</a> exception.</p> 94<p>If a Berkeley DB Concurrent Data Store database environment configured for lock timeouts was unable 95to grant a lock in the allowed time, the DbEnv::dbremove method will fail and 96either return <a href="../ref/program/errorret.html#DB_LOCK_NOTGRANTED">DB_LOCK_NOTGRANTED</a> or 97throw a <a href="../api_cxx/lockng_class.html">DbLockNotGrantedException</a> exception.</p> 98<hr size=1 noshade> 99<br><b>Class</b> 100<a href="../api_cxx/env_class.html">DbEnv</a> 101<br><b>See Also</b> 102<a href="../api_cxx/env_list.html">Database Environments and Related Methods</a> 103</tt> 104<table width="100%"><tr><td><br></td><td align=right> 105<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> 106</td></tr></table> 107<p><font size=1>Copyright (c) 1996,2008 Oracle. 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