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187 lines
7.2 KiB
HTML
187 lines
7.2 KiB
HTML
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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<title>Putting Records Using Cursors</title>
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<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Getting Started with Berkeley DB Java Edition" />
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<link rel="up" href="Cursors.html" title="Chapter 9. Using Cursors" />
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<link rel="prev" href="Positioning.html" title="Getting Records Using the Cursor" />
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<link rel="next" href="DeleteEntryWCursor.html" title="Deleting Records Using Cursors" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 12.2.7.5</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">Putting Records Using Cursors</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="Positioning.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 9. Using Cursors</th>
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<td width="20%" align="right"> <a accesskey="n" href="DeleteEntryWCursor.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="PutEntryWCursor"></a>Putting Records Using Cursors</h2>
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</div>
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</div>
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</div>
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<p>
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You can use cursors to put records into the database. JE's behavior
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when putting records into the database differs depending on whether the
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database supports duplicate records. If duplicates are allowed, its
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behavior also differs depending on whether a comparator is provided for
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the database. (Comparators are described in
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<a class="xref" href="comparator.html" title="Using Comparators">Using Comparators</a>).
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</p>
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<p>
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Note that when putting records to the database using a cursor, the
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cursor is positioned at the record you inserted.
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</p>
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<p>
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You can use the following methods to put records to the database:
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</p>
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<div class="itemizedlist">
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<ul type="disc">
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<li>
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<p>
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<code class="methodname">Cursor.put()</code>
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</p>
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<p>
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If the provided key does not exist in the database,
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then the order that the record is put into the database
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is determined by the BTree (key) comparator in use by the database.
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</p>
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<p>
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If the provided key already exists in the database, and the database
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does not support sorted duplicates, then the existing record data is
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replaced with the data provided on this method.
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</p>
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<p>
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If the provided key already exists in the database, and the database
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does support sorted duplicates, then the order that the record is
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inserted into the database is determined by the duplicate comparator
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in use by the database.
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</p>
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<p>
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Note that a version of this method exists which allows you to
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specify a Time to Live value for the record that you are
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inserting. See <a class="xref" href="timetolive.html" title="Using Time to Live">Using Time to Live</a>
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for more information.
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</p>
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</li>
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<li>
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<p>
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<code class="methodname">Cursor.putNoDupData()</code>
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</p>
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<p>
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If the provided key <span>and data</span> already exists
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in the database, then this method returns
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<code class="literal">OperationStatus.KEYEXIST</code>.
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</p>
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<p>
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If the key does not exist, then the order that the record is put into the database
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is determined by the
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<span>
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BTree (key) comparator in use by the database.
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</span>
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</p>
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<span></span>
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</li>
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<li>
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<p>
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<code class="methodname">Cursor.putNoOverwrite()</code>
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</p>
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<p>
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If the provided key already exists
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in the database, then this method returns
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<code class="literal">OperationStatus.KEYEXIST</code>.
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</p>
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<p>
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If the key does not exist, then the order that the record is put into the database
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is determined by the BTree (key) comparator in use by the database.
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</p>
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</li>
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</ul>
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</div>
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<p>For example:</p>
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<a id="je_cursor7"></a>
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<pre class="programlisting">package je.gettingStarted;
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import com.sleepycat.je.Cursor;
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import com.sleepycat.je.Database;
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import com.sleepycat.je.DatabaseEntry;
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import com.sleepycat.je.OperationStatus;
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...
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// Create the data to put into the database
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String key1str = "My first string";
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String data1str = "My first data";
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String key2str = "My second string";
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String data2str = "My second data";
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String data3str = "My third data";
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Cursor cursor = null;
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try {
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...
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// Database and environment open omitted for brevity
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...
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DatabaseEntry key1 = new DatabaseEntry(key1str.getBytes("UTF-8"));
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DatabaseEntry data1 = new DatabaseEntry(data1str.getBytes("UTF-8"));
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DatabaseEntry key2 = new DatabaseEntry(key2str.getBytes("UTF-8"));
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DatabaseEntry data2 = new DatabaseEntry(data2str.getBytes("UTF-8"));
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DatabaseEntry data3 = new DatabaseEntry(data3str.getBytes("UTF-8"));
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// Open a cursor using a database handle
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cursor = myDatabase.openCursor(null, null);
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// Assuming an empty database.
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OperationStatus retVal = cursor.put(key1, data1); // SUCCESS
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retVal = cursor.put(key2, data2); // SUCCESS
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retVal = cursor.put(key2, data3); // SUCCESS if dups allowed,
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// KEYEXIST if not.
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} catch (Exception e) {
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// Exception handling goes here
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} finally {
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// Make sure to close the cursor
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cursor.close();
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}</pre>
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</div>
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<div class="navfooter">
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<hr />
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<table width="100%" summary="Navigation footer">
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<tr>
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<td width="40%" align="left"><a accesskey="p" href="Positioning.html">Prev</a> </td>
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<td width="20%" align="center">
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<a accesskey="u" href="Cursors.html">Up</a>
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</td>
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<td width="40%" align="right"> <a accesskey="n" href="DeleteEntryWCursor.html">Next</a></td>
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</tr>
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<tr>
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<td width="40%" align="left" valign="top">Getting Records Using the Cursor </td>
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<td width="20%" align="center">
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<a accesskey="h" href="index.html">Home</a>
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</td>
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<td width="40%" align="right" valign="top"> Deleting Records Using Cursors</td>
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</tr>
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</table>
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</div>
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</body>
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</html>
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