131 lines
8.5 KiB
HTML
131 lines
8.5 KiB
HTML
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<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" 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="dc.language" scheme="rfc1766" 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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<meta name="dc.date" scheme="iso8601" content="2005-09-19" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="security" content="public" />
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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="keywords" content="identifiers, SQL (Structured Query Language),
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description, in SQL, ordinary identifier, ordinary, reserved words, reserved,
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words, delimited identifier, escape character in SQL, escape character,
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' (apostrophe), ' (quotation mark), delimited, in system names,
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system identifier, system, host identifier, host" />
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<title>Identifiers</title>
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<link rel="stylesheet" type="text/css" href="ibmidwb.css" />
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<link rel="stylesheet" type="text/css" href="ic.css" />
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</head>
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<body>
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<a id="Top_Of_Page" name="Top_Of_Page"></a><!-- Java sync-link -->
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<script language = "Javascript" src = "../rzahg/synch.js" type="text/javascript"></script>
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<a name="ch2iden"></a>
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<h2 id="ch2iden"><a href="rbafzmst02.htm#ToC_83">Identifiers</a></h2><a id="idx232" name="idx232"></a><a id="idx233" name="idx233"></a>
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<p>An <span class="italic">identifier</span> is a token used to form a name. An
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identifier in an SQL statement is one of the following types:</p>
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<ul>
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<li><a href="rbafzmstch2iden.htm#sqlidts">SQL identifiers</a></li>
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<li><a href="rbafzmstch2iden.htm#ch2sysident">System identifiers</a></li>
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<li><a href="rbafzmstch2iden.htm#ch2hostiden">Host identifiers</a></li></ul><p class="indatacontent"> </p>
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<a name="wq66"></a>
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<div class="notetitle" id="wq66">Note:</div>
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<div class="notebody">$, @, #, and all other variant characters should not
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be used in identifiers because the code points used to represent them vary
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depending on the CCSID of the string in which they are contained. If they
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are used, unpredictable results may occur. For more information about variant
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characters, see the <a href="../nls/rbagsdb2qmansqlsortseq.htm">Variant characters</a> topic in
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the iSeries Information Center.</div>
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<a name="sqlidts"></a>
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<h3 id="sqlidts"><a href="rbafzmst02.htm#ToC_84">SQL identifiers</a></h3>
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<p><a id="idx234" name="idx234"></a><a id="idx235" name="idx235"></a><a id="idx236" name="idx236"></a><a id="idx237" name="idx237"></a><a id="idx238" name="idx238"></a><a id="idx239" name="idx239"></a><a id="idx240" name="idx240"></a><a id="idx241" name="idx241"></a><a id="idx242" name="idx242"></a><a id="idx243" name="idx243"></a><a id="idx244" name="idx244"></a><a id="idx245" name="idx245"></a></p>
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<p>There are two types of SQL identifiers: <span class="italic">ordinary identifiers</span> and <span class="italic">delimited identifiers</span>. </p>
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<ul>
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<li>An <span class="italic">ordinary identifier</span> is an uppercase letter
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followed by zero or more characters, each of which is an uppercase letter,
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a digit, or the underscore character. Note that ordinary identifiers are converted
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to uppercase. An ordinary identifier should not be a reserved word. See <a href="rbafzmstresword.htm#resword">Appendix H. Reserved schema names and reserved words</a> for a list of reserved words. If a reserved word is used
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as an identifier in SQL, it should be specified in uppercase and must be a
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delimited identifier or specified in a variable.</li>
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<li>A <span class="italic">delimited identifier</span> is a sequence of one or
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more characters enclosed within SQL escape characters. The sequence must consist
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of one or more characters. Leading blanks in the sequence are significant.
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Trailing blanks in the sequence are not significant. The length of a delimited
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identifier does not include the two SQL escape characters. Note that delimited
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identifiers are not converted to uppercase. The escape character is the quotation
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mark (") except in the following cases where the escape character is the
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apostrophe ('):
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<ul>
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<li>Interactive SQL when the SQL string delimiter is set to the quotation
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mark in COBOL syntax checking statement mode</li>
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<li>Dynamic SQL in a COBOL program when the CRTSQLCBL or CRTSQLCBLI parameter
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OPTION(*QUOTESQL) specifies that the string delimiter is the quotation mark
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(")</li>
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<li>COBOL application program when the CRTSQLCBL or CRTSQLCBLI parameter OPTION(*QUOTESQL)
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specifies that the string delimiter is the quotation mark (")</li></ul>
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<p>The following characters are not allowed within delimited identifiers: </p>
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<ul>
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<li><span class="hex">X'00'</span> through <span class="hex">X'3F'</span> and <span class="hex">X'FF'</span></li></ul></li></ul>
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<a name="ch2sysident"></a>
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<h3 id="ch2sysident"><a href="rbafzmst02.htm#ToC_85">System identifiers</a></h3><a id="idx246" name="idx246"></a><a id="idx247" name="idx247"></a>
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<p>A system identifier is used to form the name of system objects in i5/OS.
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There are two types of system identifiers: ordinary identifiers and delimited
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identifiers. </p>
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<ul>
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<li>The rules for forming a system ordinary identifier are identical to the
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rules for forming an SQL ordinary identifier.</li>
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<li>The rules for forming a system delimited identifier are identical to those
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for forming SQL delimited identifiers, except:
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<ul>
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<li>The following special characters are not allowed in a delimited system
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identifier:
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<ul>
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<li>A blank (<span class="hex">X'40'</span>)</li>
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<li>An asterisk (<span class="hex">X'5C'</span>)</li>
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<li>An apostrophe (<span class="hex">X'7D'</span>)</li>
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<li>A question mark (<span class="hex">X'6F'</span>)</li>
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<li>A quotation mark (<span class="hex">X'7F'</span>)</li></ul></li>
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<li>The bytes required for the escape characters are included in the length
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of the identifier unless the characters within the delimiters would form an
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ordinary identifier.
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<p>For example, "PRIVILEGES" is in uppercase
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and the characters within the delimiters form an ordinary identifier; therefore,
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it has a length of 10 bytes and is a valid system name for a column. On the
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other hand, "privileges" is in lowercase, has a length of 12 bytes,
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and is not a valid system name for a column because the bytes required for
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the delimiters must be included in the length of the identifier.</p></li></ul></li></ul>
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<a name="wq67"></a>
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<h4 id="wq67">Examples</h4>
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<p></p>
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<pre class="xmp"> WKLYSAL WKLY_SAL "WKLY_SAL" "UNION" "wkly_sal"</pre>
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<a name="ch2hostiden"></a>
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<h3 id="ch2hostiden"><a href="rbafzmst02.htm#ToC_87">Host identifiers</a></h3><a id="idx248" name="idx248"></a><a id="idx249" name="idx249"></a>
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<p>A <var class="pv">host-identifier</var> is a name declared in the host
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program. The rules for forming a host-identifier are the rules of the host
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language; except that DBCS characters cannot be used. For example, the rules
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for forming a host-identifier in a COBOL program are the same as the rules
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for forming a user-defined word in COBOL. Names beginning with the characters 'SQ'<sup class="fn"><a href="rbafzmstch2iden.htm#fn9">16</a></sup>, 'SQL', 'sql', 'RDI', or 'DSN'
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should not be used because precompilers generate host variables that begin
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with these characters. <span>In Java™, do not use names beginning with <tt class="xph">'__sJT_'</tt>.</span></p>
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<p>See <a href="rbafzmstch2nam.htm#bable1">Table 2</a> for the limits on the maximum size of the host
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identifier name imposed by DB2 UDB for iSeries.</p>
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<hr /><div class="fnnum"><a id="fn9" name="fn9">16</a>.</div>
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<div class="fntext">'SQ' is allowed in C, COBOL, and PL/I; it should not
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be used in RPG.</div>
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<br />
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<hr /><br />
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[ <a href="#Top_Of_Page">Top of Page</a> | <a href="rbafzmstch2tok.htm">Previous Page</a> | <a href="rbafzmstch2nam.htm">Next Page</a> | <a href="rbafzmst02.htm#wq1">Contents</a> |
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<a href="rbafzmstindex.htm#index">Index</a> ]
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<a id="Bot_Of_Page" name="Bot_Of_Page"></a>
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</body>
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</html>
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