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This help page requires JavaScript to render correctly.</noscript> </head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii" /> <meta http-equiv="Content-Style-Type" content="text/css" /> <meta http-equiv="Content-Script-Type" content="text/javascript" /> <meta name="generator" content="Oracle DARB XHTML Converter (Mode = ohj/ohw) - Version 5.1.1 Build 005" /> <meta name="date" content="2009-04-21T9:46:24Z" /> <meta name="robots" content="noarchive" /> <meta name="doctitle" content="Declaring and Assigning Values to Variables and Constants" /> <meta name="relnum" content="11g Release 2 (11.2)" /> <meta name="partnum" content="E10766-01" /> <link rel="copyright" href="./dcommon/html/cpyr.htm" title="Copyright" type="text/html" /> <link rel="stylesheet" href="./dcommon/css/blafdoc.css" title="Oracle BLAFDoc" type="text/css" /> <link rel="contents" href="toc.htm" title="Contents" type="text/html" /> <link rel="prev" href="tdddg_subprograms017.htm" title="Previous" type="text/html" /> <link rel="next" href="tdddg_subprograms019.htm" title="Next" type="text/html" /> <title>Declaring and Assigning Values to Variables and Constants</title> </head> <body> <div class="zz-skip-header"><a href="#BEGIN">Skip Headers</a></div> <table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%"> <col width="86%" /> <col width="*" /> <tr valign="bottom"> <td align="left"></td> <td align="center"><a href="tdddg_subprograms017.htm"><img width="24" height="24" src="./dcommon/gifs/leftnav.gif" alt="Previous" /><br /> <span class="icon">Previous</span></a> </td> <td align="center"><a href="tdddg_subprograms019.htm"><img width="24" height="24" src="./dcommon/gifs/rightnav.gif" alt="Next" /><br /> <span class="icon">Next</span></a></td> </tr> </table> <p><a id="CIHBCBHC" name="CIHBCBHC"></a><a id="TDDDG42000" name="TDDDG42000"></a></p> <div class="sect1"><!-- infolevel="all" infotype="General" --> <h1>Declaring and Assigning Values to Variables and Constants</h1> <a name="BEGIN" id="BEGIN"></a> <p>One significant advantage that PL/SQL has over SQL is that PL/SQL lets you declare and use variables and constants.</p> <p>A variable or constant declared in a package specification can be used by any program that has access to the package. A variable or constant declared in a package body or subprogram is <a id="sthref395" name="sthref395"></a><a id="sthref396" name="sthref396"></a><a id="sthref397" name="sthref397"></a><a id="sthref398" name="sthref398"></a><a id="sthref399" name="sthref399"></a><a id="sthref400" name="sthref400"></a><a id="sthref401" name="sthref401"></a><a id="sthref402" name="sthref402"></a>local to that package or subprogram.</p> <p>A <a id="sthref403" name="sthref403"></a><span class="bold">variable</span> holds a value of a particular data type. Your program can change the value at run time. A <a id="sthref404" name="sthref404"></a><span class="bold">constant</span> holds a value that cannot be changed.</p> <p>A variable or constant can have any PL/SQL data type. When declaring a variable, you can assign it an initial value; if you do not, its initial value is <code>NULL</code>. When declaring a constant, you must assign it an <a id="sthref405" name="sthref405"></a>initial value. To assign an initial value to a variable or constant, use the <a id="sthref406" name="sthref406"></a>assignment operator (<code>:=</code>).</p> <div align="center"> <div class="inftblnotealso"><br /> <table class="NoteAlso oac_no_warn" summary="" cellpadding="3" cellspacing="0"> <tbody> <tr> <td align="left"> <p class="notep1">Tip:</p> Declare all values that do not change as constants. This practice optimizes your compiled code and makes your source code easier to maintain.</td> </tr> </tbody> </table> <br /></div> <!-- class="inftblnotealso" --></div> <p>This section contains:</p> <ul> <li> <p><a href="tdddg_subprograms019.htm#CIHBGDBA">Tutorial: Declaring Variables and Constants in a Subprogram</a></p> </li> <li> <p><a href="tdddg_subprograms020.htm#BABBHBGA">Ensuring that Variables, Constants, and Parameters Have Correct Data Types</a></p> </li> <li> <p><a href="tdddg_subprograms021.htm#BABEEIIC">Tutorial: Changing Declarations to Use the %TYPE Attribute</a></p> </li> <li> <p><a href="tdddg_subprograms022.htm#CIHBFAGE">Assigning Values to Variables</a></p> </li> </ul> <div class="helpinfonotealso"> <h2>Related Topics</h2> <p><a href="javascript:open('http://www.oracle.com/pls/db112/lookup?id=LNPLS00202','newWindow').focus()"><span class="italic">Oracle Database PL/SQL Language Reference</span></a></p> <p><a href="tdddg_subprograms.htm#CIHDFDJG">Developing Stored Subprograms and Packages</a></p> </div> <!-- Start Footer --> <div class="footer"> <table class="simple oac_no_warn" summary="" cellspacing="0" cellpadding="0" width="100%"> <col width="86%" /> <col width="*" /> <tr> <td align="left"><span class="copyrightlogo">Copyright © 1996, 2009, Oracle and/or its affiliates. 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