<!--$Id: seq_open.so,v 1.9 2005/01/20 01:15:15 ubell Exp $--> <!--Copyright (c) 1997,2008 Oracle. All rights reserved.--> <!--See the file LICENSE for redistribution information.--> <html> <head> <title>Berkeley DB: DB_SEQUENCE->open</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_SEQUENCE->open</b> </td> <td align=right> <a href="../api_c/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.h> <p> int DB_SEQUENCE->open(DB_SEQUENCE *seq, DB_TXN *txnid, DBT *key, u_int32_t flags); <p> int DB_SEQUENCE->get_dbp(DB_SEQUENCE *seq, DB **dbp); <p> int DB_SEQUENCE->get_key(DB_SEQUENCE *seq, DBT *key); <p> int </pre></b> <hr size=1 noshade> <b>Description: DB_SEQUENCE->open</b> <p>The DB_SEQUENCE->open method opens the sequence represented by the <b>key</b>. The key must be compatible with the underlying database specified in the corresponding call to <a href="../api_c/seq_class.html">db_sequence_create</a>.</p> <b>Parameters</b> <br> <b>key</b><ul compact><li>The <b>key</b> specifies which record in the database stores the persistent sequence data.</ul> <b>flags</b><ul compact><li>The <b>flags</b> parameter must be set to 0 or by bitwise inclusively <b>OR</b>'ing together one or more of the following values: <br> <b><a name="DB_CREATE">DB_CREATE</a></b><ul compact><li>Create the sequence. If the sequence does not already exist and the DB_CREATE flag is not specified, the DB_SEQUENCE->open will fail.</ul> <b><a name="DB_EXCL">DB_EXCL</a></b><ul compact><li>Return an error if the sequence already exists. The <a href="../api_c/db_open.html#DB_EXCL">DB_EXCL</a> flag is only meaningful when specified with the <a href="../api_c/env_open.html#DB_CREATE">DB_CREATE</a> flag.</ul> <b><a name="DB_THREAD">DB_THREAD</a></b><ul compact><li>Cause the <a href="../api_c/seq_class.html">DB_SEQUENCE</a> handle returned by DB_SEQUENCE->open to be <i>free-threaded</i>; that is, usable by multiple threads within a single address space. Note that if multiple threads create multiple sequences using the same database handle that handle must have been opened specifying <a name="DB_THREAD">DB_THREAD</a>.</ul> <br></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_c/txn_begin.html">DB_ENV->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_c/env_cdsgroup_begin.html">DB_ENV->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. Transactionally protected operations on a <a href="../api_c/seq_class.html">DB_SEQUENCE</a> handle require the <a href="../api_c/seq_class.html">DB_SEQUENCE</a> handle itself be transactionally protected during its open if the open creates the sequence.</ul> <br> <hr size=1 noshade> <b>Description: DB_SEQUENCE->get_dbp</b> <p>The DB_SEQUENCE->get_dbp method returns the database handle.</p> <b>Parameters</b> <br> <b>dbp</b><ul compact><li>The <b>dbp</b> parameter references memory into which a pointer to the database handle is copied.</ul> <br> <p>The DB_SEQUENCE->get_dbp method may be called at any time during the life of the application.</p> <p>The DB_SEQUENCE->get_dbp method returns a non-zero error value on failure and 0 on success. </p> <hr size=1 noshade> <b>Description: DB_SEQUENCE->get_key</b> <p>The DB_SEQUENCE->get_key method returns the key for the sequence.</p> <b>Parameters</b> <br> <b>key</b><ul compact><li>The <b>key</b> parameter references memory into which a pointer to the key data is copied.</ul> <br> <p>The DB_SEQUENCE->get_key method may be called at any time during the life of the application.</p> <p>The DB_SEQUENCE->get_key method returns a non-zero error value on failure and 0 on success. </p> <hr size=1 noshade> <br><b>Class</b> <a href="../api_c/seq_class.html">DB_SEQUENCE</a> <br><b>See Also</b> <a href="../api_c/seq_list.html">Sequences and Related Methods</a> </tt> <table width="100%"><tr><td><br></td><td align=right> <a href="../api_c/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>