76 lines
4.6 KiB
HTML
76 lines
4.6 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="security" content="public" />
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<meta name="Robots" content="index,follow" />
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<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))' />
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<meta name="DC.Type" content="reference" />
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<meta name="DC.Title" content="Example 3: Define fields derived from existing field definitions" />
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<meta name="abstract" content="This example shows the use of derived fields and built-in functions." />
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<meta name="description" content="This example shows the use of derived fields and built-in functions." />
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<meta name="DC.Relation" scheme="URI" content="rbafofdefd.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="rbafofdefdex3" />
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<meta name="DC.Language" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Example 3: Define fields derived from existing field definitions</title>
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</head>
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<body id="rbafofdefdex3"><a name="rbafofdefdex3"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Example 3: Define fields derived from existing field definitions</h1>
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<div><p>This example shows the use of derived fields and built-in functions.</p>
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<div class="section"><div class="p">Assume, in the previous example, that a field called <em>Fldx</em> also
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exists in FILEA, and the <em>Fldx</em> field has appropriate attributes used
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to hold the sine of the <em>Fldm</em> field. Also assume that you are not using
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the contents of the <em>Fldx</em> field. You can use the MAPFLD parameter to
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change the contents of a field before passing it to your high-level language
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program. For example, you can specify: <pre>OVRDBF FILE(FILEA) SHARE(*YES)
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OPNQRYF FILE(FILEA) MAPFLD((FLDX '%SIN(FLDM)'))
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CALL PGM(PGMF) /* Created using file FILEA as input */
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CLOF OPNID(FILEA)
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DLTOVR FILE(FILEA)</pre>
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</div>
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</div>
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<div class="section"><p>In this case, you do not need to specify a different record format
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on the FORMAT parameter. (The default uses the format of the first file on
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the FILE parameter.) Therefore, the program is created by using FILEA. When
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using this technique, you must ensure that the field you redefine has attributes
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that allow the calculated value to process correctly. The least complicated
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approach is to create a separate file with the specific fields you want to
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process for each query.</p>
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</div>
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<div class="section"><p>You can also use this technique with a mapped field definition
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and the %XLATE function to translate a field so that it appears to the program
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in a different manner than what exists in the database. For example, you can
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translate a lowercase field so the program only sees uppercase.</p>
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</div>
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<div class="section"><div class="p">The sort sequence and language identifier can affect the results
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of the %MIN and %MAX built-in functions. For example, the uppercase and lowercase
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versions of letters can be equal or unequal depending on the selected sort
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sequence and language identifier. <div class="note"><span class="notetitle">Note:</span> The translated field value is used
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to determine the minimum and maximum, but the untranslated value is returned
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in the result record.</div>
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</div>
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</div>
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<div class="section"><p>The example described uses FILEA as an input file. You can also
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update data using the Open Query File (OPNQRYF) command. However, if you use
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a mapped field definition to change a field, updates to the field are ignored.</p>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rbafofdefd.htm" title="Listed here are the operations allowed by defining fields derived from existing field definitions.">Define fields derived from existing field definitions</a></div>
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</div>
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</div>
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</body>
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</html>
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