1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
<!--$Id: db_truncate.so,v 1.29 2006/09/13 14:30:52 mjc Exp $-->
<!--Copyright (c) 1997,2008 Oracle. All rights reserved.-->
<!--See the file LICENSE for redistribution information.-->
<html>
<head>
<title>Berkeley DB: Db::truncate</title>
<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++">
</head>
<body bgcolor=white>
<table width="100%"><tr valign=top>
<td>
<b>Db::truncate</b>
</td>
<td align=right>
<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></td>
</tr></table>
<hr size=1 noshade>
<tt>
<b><pre>
#include <db_cxx.h>
<p>
int
Db::truncate(DbTxn *txnid, u_int32_t *countp, u_int32_t flags);
</pre></b>
<hr size=1 noshade>
<b>Description: Db::truncate</b>
<p>The Db::truncate method empties the database, discarding all records
it contains. The number of records discarded from the database is
returned in <b>countp</b>.</p>
<p>When called on a database configured with secondary indices using the
<a href="../api_cxx/db_associate.html">Db::associate</a> method, the Db::truncate method truncates the primary
database and all secondary indices. A count of the records discarded
from the primary database is returned.</p>
<p>It is an error to call the Db::truncate method on a database with open
cursors.</p>
<p>The Db::truncate method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</p>
<b>Parameters</b> <br>
<b>countp</b><ul compact><li>The <b>countp</b> parameter references memory into which
the number of records discarded from the database is copied.</ul>
<b>flags</b><ul compact><li>The <b>flags</b> parameter is currently unused, and must be set to 0.</ul>
<b>txnid</b><ul compact><li>If the operation is part of an application-specified transaction, the
<b>txnid</b> parameter is a transaction handle returned from
<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
<b>txnid</b> parameter is a handle returned from
<a href="../api_cxx/env_cdsgroup_begin.html">DbEnv::cdsgroup_begin</a>; otherwise NULL.
If no transaction handle is
specified, but the
operation occurs in a transactional
database,
the operation will be implicitly transaction protected.
</ul>
<br>
<br><b>Errors</b>
<p>The Db::truncate method
may fail and throw
<a href="../api_cxx/except_class.html">DbException</a>,
encapsulating one of the following non-zero errors, or return one of
the following non-zero errors:</p>
<br>
<b>EINVAL</b><ul compact><li>If there are open cursors in the database; or if an
invalid flag value or parameter was specified.</ul>
<br>
<p>If a transactional database environment operation was selected to
resolve a deadlock, the Db::truncate method will fail and
either return <a href="../ref/program/errorret.html#DB_LOCK_DEADLOCK">DB_LOCK_DEADLOCK</a> or
throw a <a href="../api_cxx/deadlock_class.html">DbDeadlockException</a> exception.</p>
<p>If a Berkeley DB Concurrent Data Store database environment configured for lock timeouts was unable
to grant a lock in the allowed time, the Db::truncate method will fail and
either return <a href="../ref/program/errorret.html#DB_LOCK_NOTGRANTED">DB_LOCK_NOTGRANTED</a> or
throw a <a href="../api_cxx/lockng_class.html">DbLockNotGrantedException</a> exception.</p>
<hr size=1 noshade>
<br><b>Class</b>
<a href="../api_cxx/db_class.html">Db</a>
<br><b>See Also</b>
<a href="../api_cxx/db_list.html">Databases and Related Methods</a>
</tt>
<table width="100%"><tr><td><br></td><td align=right>
<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>
</td></tr></table>
<p><font size=1>Copyright (c) 1996,2008 Oracle. All rights reserved.</font>
</body>
</html>
|
