61 lines
4.2 KiB
HTML
61 lines
4.2 KiB
HTML
<?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="Table" />
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<meta name="abstract" content="An SQL table or physical file is the base object for a query. It represents the source of the data used to produce the result set for the query. It is created by the user and specified in the FROM clause (or OPNQRYF FILE parameter)." />
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<meta name="description" content="An SQL table or physical file is the base object for a query. It represents the source of the data used to produce the result set for the query. It is created by the user and specified in the FROM clause (or OPNQRYF FILE parameter)." />
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<meta name="DC.subject" content="definitions, table create, access method, create table, create table" />
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<meta name="keywords" content="definitions, table create, access method, create table, create table" />
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<meta name="DC.Relation" scheme="URI" content="rzajqpermobj.htm" />
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<meta name="DC.Relation" scheme="URI" content="dsscan.htm" />
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<meta name="DC.Relation" scheme="URI" content="rzajqtblprobe.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="rzajqcrttbl" />
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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>Table</title>
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</head>
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<body id="rzajqcrttbl"><a name="rzajqcrttbl"><!-- --></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">Table</h1>
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<div><p>An SQL table or physical file is the base object for a query. It
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represents the source of the data used to produce the result set for the query.
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It is created by the user and specified in the FROM clause (or OPNQRYF FILE
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parameter).</p>
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<div class="section"><p>The optimizer will determine the most efficient way to extract
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the data from the table in order to satisfy the query. This may include scanning
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or probing the table or using an index to extract the data.</p>
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</div>
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<div class="section"><p>Visual explain icon: </p>
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</div>
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<div class="section"><p><img src="rzajq503.gif" alt="Table icon" /></p>
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</div>
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</div>
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<div>
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<ul class="ullinks">
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<li class="ulchildlink"><strong><a href="dsscan.htm">Table scan</a></strong><br />
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A table scan is the easiest and simplest operation that can be performed against a table. It sequentially processes all of the rows in the table to determine if they satisfy the selection criteria specified in the query. It does this in a way to maximize the I/O throughput for the table.</li>
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<li class="ulchildlink"><strong><a href="rzajqtblprobe.htm">Table probe</a></strong><br />
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A table probe operation is used to retrieve a specific row from a table based upon its row number. The row number is provided to the table probe access method by some other operation that generates a row number for the table.</li>
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</ul>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rzajqpermobj.htm" title="The database objects and access methods used by the query engine can be broken down into three basic types of operations that are used to manipulate the permanent and temporary objects -- Create, Scan, and Probe.">Permanent objects and access methods</a></div>
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</div>
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</div>
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</body>
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</html> |