50 lines
3.6 KiB
HTML
50 lines
3.6 KiB
HTML
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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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<meta name="DC.Title" content="Performance comparisons with other database functions" />
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<meta name="abstract" content="The Open Query File (OPNQRYF) command uses the same database support as logical files and join logical files. Therefore, the performance of functions like building a keyed access path or doing a join operation is the same." />
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<meta name="description" content="The Open Query File (OPNQRYF) command uses the same database support as logical files and join logical files. Therefore, the performance of functions like building a keyed access path or doing a join operation is the same." />
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<meta name="DC.subject" content="performance, comparisons with other database functions" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<title>Performance comparisons with other database functions</title>
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</head>
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<body id="rbafooqfpcoth"><a name="rbafooqfpcoth"><!-- --></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">Performance comparisons with other database functions</h1>
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<div><p>The Open Query File (OPNQRYF) command uses the same database support
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as logical files and join logical files. Therefore, the performance of functions
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like building a keyed access path or doing a join operation is the same.</p>
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<p>The selection functions done by the OPNQRYF command (for
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the QRYSLT and GRPSLT parameters) are similar to logical file select/omit.
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The main difference is that for the OPNQRYF command, the system decides whether
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to use access path selection or dynamic selection (similar to omitting or
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specifying the DYNSLT keyword in the DDS for a logical file), as a result
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of the access paths available on the system and what value was specified on
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the OPTIMIZE parameter.</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="rbafoopnqf.htm" title="The Open Query File (OPNQRYF) command is a control language (CL) command that allows you to perform many data processing functions on database files. These topics discuss how to create a query using the OPNQRYF command, how to specify parameters for its major functions, and how to use it with your high-level language program.">Use Open Query File (OPNQRYF) command</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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