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18          <th colspan="3" align="center">Secondary Indices with Transaction Applications</th>
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32            <h2 class="title" style="clear: both"><a id="txnindices"></a>Secondary Indices with Transaction Applications</h2>
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37      <p>
38            <span>
39            You 
40            </span>
41            
42
43                can use transactions with your secondary indices so long as you
44
45            <span>
46                open the secondary index so that it supports transactions (that is,
47                you wrap the database open in a transaction, or use auto commit,
48                in the same way as when you open a primary transactional database).
49            </span>
50
51            
52                
53            <span>
54                In addition, you must make sure that when you associate the
55                secondary index with the primary database, the association is
56                performed using a transaction. The easiest thing to do here is
57                to simply specify <tt class="literal">DB_AUTO_COMMIT</tt> when you
58                perform the association.
59            </span>
60        </p>
61      <p>
62            All other aspects of using secondary indices with transactions are
63            identical to using secondary indices without transactions. In
64            addition, transaction-protecting 
65                <span>
66                    cursors opened against secondary indices is performed in
67                    exactly the same way as when you use transactional cursors
68                    against a primary database. 
69                </span>
70                
71                    See <a href="txncursor.html">Transactional Cursors</a> for details.
72        </p>
73      <p>
74            Note that when you use transactions to protect your database writes, your secondary indices are protected from
75            corruption because updates to the primary and the secondaries are performed in a single atomic transaction.
76        </p>
77      <p>
78            For example:
79        </p>
80      <pre class="programlisting">#include &lt;db.h&gt;
81
82...
83
84DB_ENV *envp;      /* Environment pointer */
85DB *dbp, *sdbp;    /* Primary and secondary DB handles */
86u_int32_t flags;   /* Primary database open flags */
87int ret;           /* Function return value */
88
89/* Environment and primary database opens omitted */
90
91/* Secondary */
92ret = db_create(&amp;sdbp, envp, 0);
93if (ret != 0) {
94  /* Error handling goes here */
95}
96/* open the secondary database */
97ret = sdbp-&gt;open(sdbp,          /* DB structure pointer */
98                 NULL,            /* Transaction pointer */
99                 "my_secdb.db",   /* On-disk file that holds the database. */
100                 NULL,            /* Optional logical database name */
101                 DB_BTREE,        /* Database access method */
102                 DB_AUTO_COMMIT,  /* Open flags */
103                 0);              /* File mode (using defaults) */
104if (ret != 0) {
105  /* Error handling goes here */
106}
107
108/* Now associate the secondary to the primary */
109dbp-&gt;associate(dbp,            /* Primary database */
110               NULL,           /* TXN id */
111               sdbp,           /* Secondary database */
112               get_sales_rep,  /* Callback used for key creation. This
113                                * is described in the Getting Started
114                                * guide. */
115               DB_AUTO_COMMIT);/* Flags */</pre>
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