mirror of
https://github.com/berkeleydb/je.git
synced 2024-11-15 01:46:24 +00:00
187 lines
7.2 KiB
HTML
187 lines
7.2 KiB
HTML
|
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
|
|||
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|||
|
|
<html xmlns="http://www.w3.org/1999/xhtml">
|
|||
|
|
<head>
|
|||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
|
|||
|
|
<title>Putting Records Using Cursors</title>
|
|||
|
|
<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
|
|||
|
|
<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
|
|||
|
|
<link rel="start" href="index.html" title="Getting Started with Berkeley DB Java Edition" />
|
|||
|
|
<link rel="up" href="Cursors.html" title="Chapter 9. Using Cursors" />
|
|||
|
|
<link rel="prev" href="Positioning.html" title="Getting Records Using the Cursor" />
|
|||
|
|
<link rel="next" href="DeleteEntryWCursor.html" title="Deleting Records Using Cursors" />
|
|||
|
|
</head>
|
|||
|
|
<body>
|
|||
|
|
<div xmlns="" class="navheader">
|
|||
|
|
<div class="libver">
|
|||
|
|
<p>Library Version 12.2.7.5</p>
|
|||
|
|
</div>
|
|||
|
|
<table width="100%" summary="Navigation header">
|
|||
|
|
<tr>
|
|||
|
|
<th colspan="3" align="center">Putting Records Using Cursors</th>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="20%" align="left"><a accesskey="p" href="Positioning.html">Prev</a> </td>
|
|||
|
|
<th width="60%" align="center">Chapter 9. Using Cursors</th>
|
|||
|
|
<td width="20%" align="right"> <a accesskey="n" href="DeleteEntryWCursor.html">Next</a></td>
|
|||
|
|
</tr>
|
|||
|
|
</table>
|
|||
|
|
<hr />
|
|||
|
|
</div>
|
|||
|
|
<div class="sect1" lang="en" xml:lang="en">
|
|||
|
|
<div class="titlepage">
|
|||
|
|
<div>
|
|||
|
|
<div>
|
|||
|
|
<h2 class="title" style="clear: both"><a id="PutEntryWCursor"></a>Putting Records Using Cursors</h2>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
</div>
|
|||
|
|
<p>
|
|||
|
|
You can use cursors to put records into the database. JE's behavior
|
|||
|
|
when putting records into the database differs depending on whether the
|
|||
|
|
database supports duplicate records. If duplicates are allowed, its
|
|||
|
|
behavior also differs depending on whether a comparator is provided for
|
|||
|
|
the database. (Comparators are described in
|
|||
|
|
<a class="xref" href="comparator.html" title="Using Comparators">Using Comparators</a>).
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
Note that when putting records to the database using a cursor, the
|
|||
|
|
cursor is positioned at the record you inserted.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
You can use the following methods to put records to the database:
|
|||
|
|
</p>
|
|||
|
|
<div class="itemizedlist">
|
|||
|
|
<ul type="disc">
|
|||
|
|
<li>
|
|||
|
|
<p>
|
|||
|
|
<code class="methodname">Cursor.put()</code>
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
If the provided key does not exist in the database,
|
|||
|
|
then the order that the record is put into the database
|
|||
|
|
is determined by the BTree (key) comparator in use by the database.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
If the provided key already exists in the database, and the database
|
|||
|
|
does not support sorted duplicates, then the existing record data is
|
|||
|
|
replaced with the data provided on this method.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
If the provided key already exists in the database, and the database
|
|||
|
|
does support sorted duplicates, then the order that the record is
|
|||
|
|
inserted into the database is determined by the duplicate comparator
|
|||
|
|
in use by the database.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
Note that a version of this method exists which allows you to
|
|||
|
|
specify a Time to Live value for the record that you are
|
|||
|
|
inserting. See <a class="xref" href="timetolive.html" title="Using Time to Live">Using Time to Live</a>
|
|||
|
|
for more information.
|
|||
|
|
</p>
|
|||
|
|
</li>
|
|||
|
|
<li>
|
|||
|
|
<p>
|
|||
|
|
<code class="methodname">Cursor.putNoDupData()</code>
|
|||
|
|
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
If the provided key <span>and data</span> already exists
|
|||
|
|
in the database, then this method returns
|
|||
|
|
<code class="literal">OperationStatus.KEYEXIST</code>.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
If the key does not exist, then the order that the record is put into the database
|
|||
|
|
is determined by the
|
|||
|
|
<span>
|
|||
|
|
BTree (key) comparator in use by the database.
|
|||
|
|
</span>
|
|||
|
|
|
|||
|
|
</p>
|
|||
|
|
<span></span>
|
|||
|
|
</li>
|
|||
|
|
<li>
|
|||
|
|
<p>
|
|||
|
|
<code class="methodname">Cursor.putNoOverwrite()</code>
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
If the provided key already exists
|
|||
|
|
in the database, then this method returns
|
|||
|
|
<code class="literal">OperationStatus.KEYEXIST</code>.
|
|||
|
|
</p>
|
|||
|
|
<p>
|
|||
|
|
If the key does not exist, then the order that the record is put into the database
|
|||
|
|
is determined by the BTree (key) comparator in use by the database.
|
|||
|
|
</p>
|
|||
|
|
</li>
|
|||
|
|
</ul>
|
|||
|
|
</div>
|
|||
|
|
<p>For example:</p>
|
|||
|
|
<a id="je_cursor7"></a>
|
|||
|
|
<pre class="programlisting">package je.gettingStarted;
|
|||
|
|
|
|||
|
|
import com.sleepycat.je.Cursor;
|
|||
|
|
import com.sleepycat.je.Database;
|
|||
|
|
import com.sleepycat.je.DatabaseEntry;
|
|||
|
|
import com.sleepycat.je.OperationStatus;
|
|||
|
|
|
|||
|
|
...
|
|||
|
|
|
|||
|
|
// Create the data to put into the database
|
|||
|
|
String key1str = "My first string";
|
|||
|
|
String data1str = "My first data";
|
|||
|
|
String key2str = "My second string";
|
|||
|
|
String data2str = "My second data";
|
|||
|
|
String data3str = "My third data";
|
|||
|
|
|
|||
|
|
Cursor cursor = null;
|
|||
|
|
try {
|
|||
|
|
...
|
|||
|
|
// Database and environment open omitted for brevity
|
|||
|
|
...
|
|||
|
|
|
|||
|
|
DatabaseEntry key1 = new DatabaseEntry(key1str.getBytes("UTF-8"));
|
|||
|
|
DatabaseEntry data1 = new DatabaseEntry(data1str.getBytes("UTF-8"));
|
|||
|
|
DatabaseEntry key2 = new DatabaseEntry(key2str.getBytes("UTF-8"));
|
|||
|
|
DatabaseEntry data2 = new DatabaseEntry(data2str.getBytes("UTF-8"));
|
|||
|
|
DatabaseEntry data3 = new DatabaseEntry(data3str.getBytes("UTF-8"));
|
|||
|
|
|
|||
|
|
// Open a cursor using a database handle
|
|||
|
|
cursor = myDatabase.openCursor(null, null);
|
|||
|
|
|
|||
|
|
// Assuming an empty database.
|
|||
|
|
|
|||
|
|
OperationStatus retVal = cursor.put(key1, data1); // SUCCESS
|
|||
|
|
retVal = cursor.put(key2, data2); // SUCCESS
|
|||
|
|
retVal = cursor.put(key2, data3); // SUCCESS if dups allowed,
|
|||
|
|
// KEYEXIST if not.
|
|||
|
|
|
|||
|
|
} catch (Exception e) {
|
|||
|
|
// Exception handling goes here
|
|||
|
|
} finally {
|
|||
|
|
// Make sure to close the cursor
|
|||
|
|
cursor.close();
|
|||
|
|
}</pre>
|
|||
|
|
</div>
|
|||
|
|
<div class="navfooter">
|
|||
|
|
<hr />
|
|||
|
|
<table width="100%" summary="Navigation footer">
|
|||
|
|
<tr>
|
|||
|
|
<td width="40%" align="left"><a accesskey="p" href="Positioning.html">Prev</a> </td>
|
|||
|
|
<td width="20%" align="center">
|
|||
|
|
<a accesskey="u" href="Cursors.html">Up</a>
|
|||
|
|
</td>
|
|||
|
|
<td width="40%" align="right"> <a accesskey="n" href="DeleteEntryWCursor.html">Next</a></td>
|
|||
|
|
</tr>
|
|||
|
|
<tr>
|
|||
|
|
<td width="40%" align="left" valign="top">Getting Records Using the Cursor </td>
|
|||
|
|
<td width="20%" align="center">
|
|||
|
|
<a accesskey="h" href="index.html">Home</a>
|
|||
|
|
</td>
|
|||
|
|
<td width="40%" align="right" valign="top"> Deleting Records Using Cursors</td>
|
|||
|
|
</tr>
|
|||
|
|
</table>
|
|||
|
|
</div>
|
|||
|
|
</body>
|
|||
|
|
</html>
|