118 lines
5.0 KiB
HTML
118 lines
5.0 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="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.Title" content="Example: Square of a number UDF" />
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<meta name="abstract" content="In this example, suppose that you want a function that returns the square of a number." />
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<meta name="description" content="In this example, suppose that you want a function that returns the square of a number." />
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<meta name="DC.subject" content="examples, square of a number UDF, CREATE FUNCTION statement" />
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<meta name="keywords" content="examples, square of a number UDF, CREATE FUNCTION statement" />
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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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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Example: Square of a number UDF</title>
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</head>
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<body id="rbafyudfexsqrnum"><a name="rbafyudfexsqrnum"><!-- --></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: Square of a number UDF</h1>
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<div><p>In this example, suppose that you want a function that returns
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the square of a number.</p>
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<div class="section"><p>The query statement is:</p>
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<pre><strong>SELECT</strong> SQUARE(myint) <strong>FROM</strong> mytable</pre>
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</div>
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<div class="section"> <div class="note"><span class="notetitle">Note:</span> By using the code examples, you agree to the terms of the <a href="codedisclaimer.htm">Code license and disclaimer information</a>.</div>
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</div>
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<div class="section"><p>The following examples show how to define the UDF several different
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ways.</p>
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</div>
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<div class="section"><h4 class="sectiontitle">Use an SQL function</h4><p>The CREATE FUNCTION statement:</p>
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<pre><strong>CREATE FUNCTION</strong> SQUARE( inval <strong>INT</strong>) <strong>RETURNS INT</strong>
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<strong>LANGUAGE SQL
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SET OPTION DBGVIEW=*SOURCE
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BEGIN
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RETURN</strong>(inval*inval);
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<strong>END</strong></pre>
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<p>This creates an SQL function that you can debug.</p>
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</div>
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<div class="section"><h4 class="sectiontitle">Use an external function, parameter style SQL</h4><p>The
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CREATE FUNCTION statement: </p>
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<pre><strong>CREATE FUNCTION</strong> SQUARE(<strong>INT</strong>) <strong>RETURNS INT CAST FROM FLOAT</strong>
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<strong>LANGUAGE C</strong>
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<strong>EXTERNAL NAME</strong> 'MYLIB/MATH(SQUARE)'
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<strong>DETERMINISTIC
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NO SQL
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NO EXTERNAL ACTION
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PARAMETER STYLE SQL
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ALLOW PARALLEL</strong> </pre>
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<p>The code: </p>
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<pre>void SQUARE(int *inval,
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double *outval,
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short *inind,
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short *outind,
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char *sqlstate,
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char *funcname,
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char *specname,
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char *msgtext)
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{
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if (*inind<0)
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*outind=-1;
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else
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{
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*outval=*inval;
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*outval=(*outval)*(*outval);
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*outind=0;
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}
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return;
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}</pre>
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<p>To create the external service program so it can be debugged: </p>
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<pre>CRTCMOD MODULE(mylib/square) DBGVIEW(*SOURCE)
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CRTSRVPGM SRVPGM(mylib/math) MODULE(mylib/square)
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EXPORT(*ALL) ACTGRP(*CALLER)</pre>
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</div>
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<div class="section"><h4 class="sectiontitle">Use an external function, parameter style GENERAL</h4><p>The
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CREATE FUNCTION statement:</p>
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<pre><strong>CREATE FUNCTION</strong> SQUARE(<strong>INT</strong>) <strong>RETURNS INT CAST FROM FLOAT</strong>
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<strong>LANGUAGE C
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EXTERNAL NAME</strong> 'MYLIB/MATH(SQUARE)'
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<strong>DETERMINISTIC
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NO SQL
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NO EXTERNAL ACTION
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PARAMETER STYLE GENERAL
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ALLOW PARALLEL</strong> </pre>
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<p>The code:</p>
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<pre>double SQUARE(int *inval)
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{
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double outval;
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outval=*inval;
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outval=outval*outval;
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return(outval);
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}</pre>
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<p>To create the external service program so it can be debugged: </p>
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<pre>CRTCMOD MODULE(mylib/square) DBGVIEW(*SOURCE)
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CRTSRVPGM SRVPGM(mylib/math) MODULE(mylib/square)
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EXPORT(*ALL) ACTGRP(*CALLER)</pre>
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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="rbafyuwexam.htm" title="These examples show how to implement UDF code by using SQL functions and external functions.">Examples: UDF code</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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