65 lines
5.0 KiB
HTML
65 lines
5.0 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="Describe floating-point fields in logical files" />
|
||
|
|
<meta name="abstract" content="You can use floating-point fields as mapped fields in logical files. A single- or double-precision floating-point field can be mapped to or from a zoned, packed, zero-precision binary, or another floating-point field. You cannot map between a floating-point field and a nonzero-precision binary field, a character field, a hexadecimal field, or a double-byte character set (DBCS) field." />
|
||
|
|
<meta name="description" content="You can use floating-point fields as mapped fields in logical files. A single- or double-precision floating-point field can be mapped to or from a zoned, packed, zero-precision binary, or another floating-point field. You cannot map between a floating-point field and a nonzero-precision binary field, a character field, a hexadecimal field, or a double-byte character set (DBCS) field." />
|
||
|
|
<meta name="DC.subject" content="describing, logical file, floating-point fields in, field, floating-point in logical files" />
|
||
|
|
<meta name="keywords" content="describing, logical file, floating-point fields in, field, floating-point in logical files" />
|
||
|
|
<meta name="DC.Relation" scheme="URI" content="rbafodrflf.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="rbafofpdbc" />
|
||
|
|
<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>Describe floating-point fields in logical files</title>
|
||
|
|
</head>
|
||
|
|
<body id="rbafofpdbc"><a name="rbafofpdbc"><!-- --></a>
|
||
|
|
<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
|
||
|
|
<h1 class="topictitle1">Describe floating-point fields in logical files</h1>
|
||
|
|
<div><p>You can use floating-point fields as mapped fields in logical files.
|
||
|
|
A single- or double-precision floating-point field can be mapped to or from
|
||
|
|
a zoned, packed, zero-precision binary, or another floating-point field. You
|
||
|
|
cannot map between a floating-point field and a nonzero-precision binary field,
|
||
|
|
a character field, a hexadecimal field, or a double-byte character set (DBCS)
|
||
|
|
field.</p>
|
||
|
|
<p>Mapping between floating-point fields of different precision, single or
|
||
|
|
double, or between floating-point fields and other numeric fields, can result
|
||
|
|
in rounding or a loss of precision. Mapping a double-precision floating-point
|
||
|
|
number to a single-precision floating-point number can result in rounding,
|
||
|
|
depending on the particular number involved and its internal representation.
|
||
|
|
Rounding is to the nearest (even) bit. The result always contains as much
|
||
|
|
precision as possible. A loss of precision can also occur between
|
||
|
|
two decimal numbers if the number of digits of precision is decreased.</p>
|
||
|
|
<p>You can inadvertently change the value of a field which your program did
|
||
|
|
not explicitly change. For floating-point fields, this can occur if a physical
|
||
|
|
file has a double-precision field that is mapped to a single-precision field
|
||
|
|
in a logical file, and you issue an update for the record through the logical
|
||
|
|
file. If the internal representation of the floating-point number causes it
|
||
|
|
to be rounded when it is mapped to the logical file, then updating the logical
|
||
|
|
record causes a permanent loss of precision in the physical file. If the rounded
|
||
|
|
number is the key of the physical record, then the sequence of records in
|
||
|
|
the physical file can also change.</p>
|
||
|
|
<p>A fixed-point numeric field can also be updated inadvertently if the precision
|
||
|
|
is decreased in the logical file.</p>
|
||
|
|
</div>
|
||
|
|
<div>
|
||
|
|
<div class="familylinks">
|
||
|
|
<div class="parentlink"><strong>Parent topic:</strong> <a href="rbafodrflf.htm" title="For every logical file record format described with data description specifications (DDS), you must specify a record format name and either the PFILE keyword (for simple and multiple format logical files), or the JFILE keyword (for join logical files).">Describe logical file record formats</a></div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
</body>
|
||
|
|
</html>
|