93 lines
6.2 KiB
HTML
93 lines
6.2 KiB
HTML
|
<?xml version="1.0" encoding="UTF-8"?>
|
||
|
|
<!DOCTYPE html
|
||
|
|
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
|
|
<html lang="en-us" xml:lang="en-us">
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
||
|
|
<meta name="security" content="public" />
|
||
|
|
<meta name="Robots" content="index,follow" />
|
||
|
|
<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
|
||
|
|
<meta name="DC.Type" content="reference" />
|
||
|
|
<meta name="DC.Title" content="Tips: Design distributed relational database applications" />
|
||
|
|
<meta name="abstract" content="Distributed relational database applications have different requirements from applications developed solely for use on a local database." />
|
||
|
|
<meta name="description" content="Distributed relational database applications have different requirements from applications developed solely for use on a local database." />
|
||
|
|
<meta name="DC.subject" content="application, requirements, considerations, connection management, distributed unit of work (DUW), application design tips, TCP/IP" />
|
||
|
|
<meta name="keywords" content="application, requirements, considerations, connection management, distributed unit of work (DUW), application design tips, TCP/IP" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rbal1desappnet.htm" />
|
||
|
|
<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
|
||
|
|
<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 1998, 2006" />
|
||
|
|
<meta name="DC.Format" content="XHTML" />
|
||
|
|
<meta name="DC.Identifier" content="rbal1appcons" />
|
||
|
|
<meta name="DC.Language" content="en-us" />
|
||
|
|
<!-- All rights reserved. Licensed Materials Property of IBM -->
|
||
|
|
<!-- US Government Users Restricted Rights -->
|
||
|
|
<!-- Use, duplication or disclosure restricted by -->
|
||
|
|
<!-- GSA ADP Schedule Contract with IBM Corp. -->
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ic.css" />
|
||
|
|
<title>Tips: Design distributed relational database applications</title>
|
||
|
|
</head>
|
||
|
|
<body id="rbal1appcons"><a name="rbal1appcons"><!-- --></a>
|
||
|
|
<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
|
||
|
|
<h1 class="topictitle1">Tips: Design distributed relational database applications</h1>
|
||
|
|
<div><p>Distributed relational database applications have different requirements
|
||
|
|
from applications developed solely for use on a local database.</p>
|
||
|
|
<div class="section"><p> To properly plan for these differences, design your applications
|
||
|
|
with the following considerations in mind: </p>
|
||
|
|
</div>
|
||
|
|
<div class="section"><div class="p"> <ul><li>Take advantage of the distributed unit of work (DUW) function where appropriate. <div class="note"><span class="notetitle">Note:</span> Before
|
||
|
|
Version 5 Release 1 of OS/400<sup>®</sup>, two-phase commit support was not available
|
||
|
|
with TCP/IP on the <span class="keyword">iSeries™</span> server.</div>
|
||
|
|
</li>
|
||
|
|
<li>Code programs using common interfaces.</li>
|
||
|
|
<li>Consider dividing a complex application into smaller parts and placing
|
||
|
|
each piece of the application in the location best suited to process it. One
|
||
|
|
good way to distribute processing in an application is to make use of the
|
||
|
|
SQL CALL statement to run a stored procedure at a remote location where the
|
||
|
|
data to be processed resides. The stored procedure is not limited to SQL operations
|
||
|
|
when it runs on a <span class="keyword">DB2 Universal Database™ for iSeries</span> application
|
||
|
|
server; it can use integrated database input/output or perform other types
|
||
|
|
of processing.</li>
|
||
|
|
<li>Investigate how the initial database applications will be prepared, tested,
|
||
|
|
and used.</li>
|
||
|
|
<li>Take advantage, when possible, of SQL set-processing capabilities. This
|
||
|
|
will minimize communication with the application servers. For example, update
|
||
|
|
multiple rows with one SQL statement whenever you can.</li>
|
||
|
|
<li>Be aware that database updates within a unit of work must be done at a
|
||
|
|
single site if the remote unit of work (RUW) connection method is used when
|
||
|
|
the programs are prepared, or if the other nodes in the distributed application
|
||
|
|
do not support DUW.</li>
|
||
|
|
<li>Keep in mind that the DUW connection method restricts you from directing
|
||
|
|
a single statement to more than one relational database.</li>
|
||
|
|
<li>Performance is affected by the choice of connection management methods.
|
||
|
|
Use of the RUW connection management method might be preferable if you do
|
||
|
|
not have the need to switch back and forth among different remote relational
|
||
|
|
databases. This is because more overhead is associated with the two-phase
|
||
|
|
commit protocols used with DUW connection management. <p>However, if you
|
||
|
|
have to switch frequently among multiple remote database management systems,
|
||
|
|
use DUW connection management. When running with DUW connection management,
|
||
|
|
communication conversations to one database management system do not have
|
||
|
|
to be ended when you switch the connection to another database management
|
||
|
|
system. In the like environment, this is not as big a factor as in the unlike
|
||
|
|
environment, since conversations in the like environment can be kept active
|
||
|
|
by use of the default DDMCNV(*KEEP) job definition attribute. Even in the
|
||
|
|
like environment, however, a performance advantage can be gained by using
|
||
|
|
DUW to avoid the cost of closing cursors and sending the communication flow
|
||
|
|
to establish a new connection.</p>
|
||
|
|
</li>
|
||
|
|
<li>The connection management method determines the semantics of the CONNECT
|
||
|
|
statement. With the RUW connection management method, the CONNECT statement
|
||
|
|
ends any existing connections before establishing a new connection to the
|
||
|
|
relational database. With the DUW connection management method, the CONNECT
|
||
|
|
statement does not end existing connections.</li>
|
||
|
|
</ul>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<div>
|
||
|
|
<div class="familylinks">
|
||
|
|
<div class="parentlink"><strong>Parent topic:</strong> <a href="rbal1desappnet.htm" title="Designing a distributed relational database involves making choices about applications, network considerations, and data considerations.">Design the application, network, and data for a distributed relational database</a></div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
</body>
|
||
|
|
</html>
|