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<h2 class="title" style="clear: both"><a id="ReplacingEntryWCursor"></a>Replacing Records Using Cursors</h2>
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<p>
You replace the data for a database record by using
<span>
<code class="methodname">Cursor.putCurrent()</code>.
</span>
</p>
<a id="java_cursor9"></a>
<pre class="programlisting">import com.sleepycat.db.Cursor;
import com.sleepycat.db.Database;
import com.sleepycat.db.DatabaseEntry;
import com.sleepycat.db.LockMode;
import com.sleepycat.db.OperationStatus;
...
Cursor cursor = null;
Database myDatabase = null;
try {
...
// Database open omitted for brevity
...
// Create DatabaseEntry objects
// searchKey is some String.
DatabaseEntry theKey = new DatabaseEntry(searchKey.getBytes("UTF-8"));
DatabaseEntry theData = new DatabaseEntry();
// Open a cursor using a database handle
cursor = myDatabase.openCursor(null, null);
// Position the cursor. Ignoring the return value for clarity
OperationStatus retVal = cursor.getSearchKey(theKey, theData,
LockMode.DEFAULT);
// Replacement data
String replaceStr = "My replacement string";
DatabaseEntry replacementData =
new DatabaseEntry(replaceStr.getBytes("UTF-8"));
cursor.putCurrent(replacementData);
} catch (Exception e) {
// Exception handling goes here
} finally {
// Make sure to close the cursor
cursor.close();
}</pre>
<p>
Note that you cannot change a record's key using this method; the key
parameter is always ignored when you replace a record.
</p>
<p>
When replacing the data portion of a record, if you are replacing a
record that is a member of a sorted duplicates set, then the replacement
will be successful only if the new record sorts identically to the old
record. This means that if you are replacing a record that is a member
of a sorted duplicates set, and if you are using the default
lexicographic sort, then the replacement will fail due to violating the
sort order. However, if you
provide a custom sort routine that, for example, sorts based on just a
few bytes out of the data item, then potentially you can perform
a direct replacement and still not violate the restrictions described
here.
</p>
<p>
<span>Under these circumstances, if</span>
you want to replace the data contained by a duplicate record,
<span>
and you are not using a custom sort routine, then
</span>
delete the record and create a new record with the desired key and data.
</p>
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