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<p>
<span>
You
</span>
can use transactions with your secondary indices so long as you
<span>
open the secondary index so that it supports transactions (that is,
you wrap the database open in a transaction, or use auto commit,
in the same way as when you open a primary transactional database).
</span>
<span>
In addition, you must make sure that when you associate the
secondary index with the primary database, the association is
performed using a transaction. The easiest thing to do here is
to simply specify <tt class="literal">DB_AUTO_COMMIT</tt> when you
perform the association.
</span>
</p>
<p>
All other aspects of using secondary indices with transactions are
identical to using secondary indices without transactions. In
addition, transaction-protecting
<span>
cursors opened against secondary indices is performed in
exactly the same way as when you use transactional cursors
against a primary database.
</span>
See <a href="txncursor.html">Transactional Cursors</a> for details.
</p>
<p>
Note that when you use transactions to protect your database writes, your secondary indices are protected from
corruption because updates to the primary and the secondaries are performed in a single atomic transaction.
</p>
<p>
For example:
</p>
<pre class="programlisting">#include <db_cxx.h>
...
// Environment and primary database open omitted
...
Db my_index(&envp, 0); // Secondary
// Open the secondary
my_index.open(NULL, // Transaction pointer
"my_secondary.db", // On-disk file that holds the database.
NULL, // Optional logical database name
DB_BTREE, // Database access method
DB_AUTO_COMMIT, // Open flags.
0); // File mode (using defaults)
// Now associate the primary and the secondary
my_database.associate(NULL, // Txn id
&my_index, // Associated secondary database
get_sales_rep, // Callback used for key extraction.
// This is described in the Getting
// Started guide.
DB_AUTO_COMMIT); // Flags </pre>
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