77 lines
5.7 KiB
HTML
77 lines
5.7 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="concept" />
|
||
|
|
<meta name="DC.Title" content="Specify the current access path maintenance (MAINT) parameter" />
|
||
|
|
<meta name="abstract" content="You can specify how access paths are maintained for closed files with the MAINT parameter." />
|
||
|
|
<meta name="description" content="You can specify how access paths are maintained for closed files with the MAINT parameter." />
|
||
|
|
<meta name="DC.subject" content="keeping, access paths current, access path, keeping current, specifying, delayed maintenance, access path, delayed maintenance, immediate maintenance, access path, immediate maintenance, rebuild maintenance, access path, rebuild maintenance, access path maintenance levels, database file, override, MAINT (Maintenance) parameter, Maintenance (MAINT) parameter, parameter, MAINT (Maintenance)" />
|
||
|
|
<meta name="keywords" content="keeping, access paths current, access path, keeping current, specifying, delayed maintenance, access path, delayed maintenance, immediate maintenance, access path, immediate maintenance, rebuild maintenance, access path, rebuild maintenance, access path maintenance levels, database file, override, MAINT (Maintenance) parameter, Maintenance (MAINT) parameter, parameter, MAINT (Maintenance)" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rbafocrtatt.htm" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rbafonoid16.htm" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rbafonoid17.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="rbafoapcurr" />
|
||
|
|
<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>Specify the current access path maintenance (MAINT) parameter</title>
|
||
|
|
</head>
|
||
|
|
<body id="rbafoapcurr"><a name="rbafoapcurr"><!-- --></a>
|
||
|
|
<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
|
||
|
|
<h1 class="topictitle1">Specify the current access path maintenance (MAINT) parameter</h1>
|
||
|
|
<div><p>You can specify how access paths are maintained for closed files
|
||
|
|
with the MAINT parameter.</p>
|
||
|
|
<p>While a file is open, the system maintains the access path for this file
|
||
|
|
when changes are made to the data in it. However, because more than one access
|
||
|
|
path can exist for the same data, changing data in one file might cause changes
|
||
|
|
in the access paths for other files that are not currently open (in use). </p>
|
||
|
|
<div class="p">The three ways of maintaining access paths for closed files are: <ul><li><strong>Immediate</strong> maintenance of an access path means that the access path
|
||
|
|
is maintained when changes are made to its associated data, whether the file
|
||
|
|
is open or not. Access paths used by referential constraints are always in
|
||
|
|
immediate maintenance.</li>
|
||
|
|
<li><strong>Rebuild</strong> maintenance of an access path means that the access path
|
||
|
|
is only maintained while the file is open, not when the file is closed; the
|
||
|
|
access path is rebuilt when the file is opened the next time. When a file
|
||
|
|
with rebuild maintenance is closed, the system stops maintaining the access
|
||
|
|
path. When the file is opened again, the access path is totally rebuilt. If
|
||
|
|
one or more programs have opened a specific file member with rebuild maintenance
|
||
|
|
specified, the system maintains the access path for that member until the
|
||
|
|
last user closes the file member.</li>
|
||
|
|
<li><strong>Delayed</strong> maintenance of an access path means that any maintenance
|
||
|
|
for the access path is done after the file member is opened the next time
|
||
|
|
and while it remains open. However, the access path is not rebuilt as it is
|
||
|
|
with rebuild maintenance. Changes to the access path are collected
|
||
|
|
from the time the member is closed until it is opened again. When it is opened,
|
||
|
|
only the collected changes are merged into the access path.</li>
|
||
|
|
</ul>
|
||
|
|
</div>
|
||
|
|
<p>If you do not specify the type of maintenance for a file, the default is
|
||
|
|
immediate maintenance.</p>
|
||
|
|
</div>
|
||
|
|
<div>
|
||
|
|
<ul class="ullinks">
|
||
|
|
<li class="ulchildlink"><strong><a href="rbafonoid16.htm">MAINT parameter comparison</a></strong><br />
|
||
|
|
This topic compares the influences of the immediate, rebuild, and delayed maintenances on opening and processing files.</li>
|
||
|
|
<li class="ulchildlink"><strong><a href="rbafonoid17.htm">MAINT parameter tips</a></strong><br />
|
||
|
|
The type of access path maintenance to specify depends on the number of records and the frequency of add, delete, or update operations on the file while it is closed.</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<div class="familylinks">
|
||
|
|
<div class="parentlink"><strong>Parent topic:</strong> <a href="rbafocrtatt.htm" title="When you create a database file, database attributes are stored with the file and members. You specify attributes with database command parameters.">Specify database file and member attributes</a></div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
</body>
|
||
|
|
</html>
|