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      <p>
        In general, you

            <span>will</span>
        not modify a secondary database directly. In
        order to modify a secondary database, you should modify the primary
        database and simply allow DB to manage the secondary modifications for you.
    </p>
      <p>
        However, as a convenience, you can delete

            <span>secondary database</span>
        records directly. Doing so causes the associated primary key/data pair to be deleted.
        This in turn causes DB to delete all

            <span>secondary database</span>
        records that reference the primary record.
    </p>
      <p>
        You can use the


            <tt class="methodname">Db::del()</tt>
        method to delete a secondary database record.


        <span>Note that if your
            <span>secondary database</span>

        contains duplicate records, then deleting a record from the set of
        duplicates causes all of the duplicates to be deleted as well.
        </span>

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        <h3 class="title">Note</h3>
        <p>

      <span>
        You can delete a secondary database record using the previously
        described mechanism
      </span>
      only if the primary database is opened for write access.
      </p>
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      <p>For example:</p>
      <a id="cxx_index7"></a>
      <pre class="programlisting">#include &lt;db_cxx.h&gt;
#include &lt;string.h&gt;

...

Db my_database(NULL, 0); // Primary
Db my_index(NULL, 0);    // Secondary

// Open the primary
my_database.open(NULL,       // Transaction pointer
                 "my_db.db", // On-disk file that holds the database.
                NULL,        // Optional logical database name
                DB_BTREE,    // Database access method
                DB_CREATE,   // Open flags
                0);          // File mode (using defaults)

// Setup the secondary to use sorted duplicates.
// This is often desireable for secondary databases.
my_index.set_flags(DB_DUPSORT);

// 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_CREATE,         // Open flags.
              0);                // File mode (using defaults)


// Now associate the primary and the secondary
my_database.associate(NULL,          // Txn id
                      &amp;my_index,     // Associated secondary database
                      get_sales_rep, // Callback used for key extraction.
                      0);            // Flags

// Name to delete
char *search_name = "John Doe";

// Get a search key
Dbt key(search_name, strlen(search_name) + 1);

// Now delete the secondary record. This causes the associated primary
// record to be deleted. If any other secondary databases have secondary
// records referring to the deleted primary record, then those secondary
// records are also deleted.
my_index.del(NULL, &amp;key, 0); </pre>
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