59 lines
4.2 KiB
HTML
59 lines
4.2 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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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Determine if duplicate keys exist" />
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<meta name="abstract" content="The set of keyed sequence access paths used to determine if the key is a duplicate key differs depending on the input/output (I/O) operation that is performed. You can determine if duplicate keys exist using the DUPKEYCHK parameter." />
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<meta name="description" content="The set of keyed sequence access paths used to determine if the key is a duplicate key differs depending on the input/output (I/O) operation that is performed. You can determine if duplicate keys exist using the DUPKEYCHK parameter." />
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<meta name="DC.subject" content="determining, duplicate key values, duplicate key value, DUPKEYCHK (Duplicate Key Check) parameter, Duplicate Key Check (DUPKEYCHK) parameter, parameter, DUPKEYCHK (Duplicate Key Check)" />
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<meta name="keywords" content="determining, duplicate key values, duplicate key value, DUPKEYCHK (Duplicate Key Check) parameter, Duplicate Key Check (DUPKEYCHK) parameter, parameter, DUPKEYCHK (Duplicate Key Check)" />
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<meta name="DC.Relation" scheme="URI" content="rbafoprocop.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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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Determine if duplicate keys exist</title>
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</head>
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<body id="rbafodupkey"><a name="rbafodupkey"><!-- --></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">Determine if duplicate keys exist</h1>
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<div><p>The set of keyed sequence access paths used to determine if the
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key is a duplicate key differs depending on the input/output (I/O) operation
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that is performed. You can determine if duplicate keys exist using the DUPKEYCHK
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parameter.</p>
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<p>For input operations (reads), the keyed sequence access path used is the
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one that the file is opened with. Any other keyed sequence access path that
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can exist over the physical file are not considered. Also, any records in
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the keyed sequence access path omitted because of select/omit specifications
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are not considered when deciding if the key operation is a duplicate.</p>
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<p>For output (write) and update operations, all nonunique keyed sequence
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access paths of *IMMED maintenance that exist over the physical file are searched
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to determine if the key for this output or update operation is a duplicate.
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Only keyed sequence access paths that have *REBLD and *DLY maintenance
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are considered if the access paths are actively open over the file at feedback
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time.</p>
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<p>When you process a keyed file with a COBOL program, you can specify duplicate
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key feedback to be returned to your program through the COBOL language, or
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on the Open Database File (OPNDBF) or Open Query File (OPNQRYF) command. However,
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in COBOL, having duplicate key feedback returned can cause a decline in performance.</p>
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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="rbafoprocop.htm" title="These topics describe several runtime processing options.">File processing options</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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