chap16_8.html
来自「Oracle资料大集合」· HTML 代码 · 共 342 行
HTML
342 行
<HTML><HEAD><TITLE>Oracle8 How-To</TITLE><SCRIPT><!--function displayWindow(url, width, height) { var Win = window.open(url,"displayWindow",'width=' + width +',height=' + height + ',resizable=1,scrollbars=yes');}//--></SCRIPT></HEAD><BODY BACKGROUND="../../../images/curve_itlibrary_white.gif" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#DD0000" VLINK="#999999" ALINK="#FF0000"><!--Begin Header Table --><TABLE width="640" cellpadding="0" cellspacing="0" border="0"><TR><TD VALIGN="TOP" WIDTH="640" COLSPAN="3"><A HREF="http://www.earthweb.com" target="resource window"><IMG SRC="../../../images/eweb_banner.gif" VSPACE="6" WIDTH="640" HEIGHT="25" ALT="Brought to you by EarthWeb" border="0"><BR></a></TD></TR><TR><TD VALIGN="TOP" WIDTH="150"><A HREF="http://www.itlibrary.com/"><IMG SRC="../../../images/small_logo.gif" WIDTH=103 HEIGHT=82 ALT="IT Library Logo" border="0"></a><P><!--Begin Subscribe Box Table --><TABLE border="0" cellpadding="0" cellspacing="0" WIDTH="100"><TR><TD></TD></TR></TABLE><!--End Subscribe Box Table --></td><TD><img src="../../../images/dotclear.gif" WIDTH="15" HEIGHT="1"></TD><TD><!-- Begin Ads itl //--><a href="http://www.itlibrary.com/adclick.html/CID=00000349829b438e00000000/site=itlibrary/area=itl/aamsz=468x60" TARGET="new win"><img src="../../../../adimages.earthweb.com/images/ads/spidercatcher.gif@10331" ALT="Click Here!" border="0"><BR><CENTER>Click Here!</CENTER></a><!-- itl End Ads //--></td></TR></TABLE><!--End Header Table --><!--Begin Main Table --><TABLE width="640" cellpadding="0" cellspacing="0" border="0"><TR><!--Begin Left Navigation column --><TD VALIGN="TOP" WIDTH="140"><FORM action="/subscribe/list.cgi" method="post"><INPUT name='email' value='your e-mail' size="11"><INPUT type='hidden' name='state' value='Subscribe'><br><INPUT type='image' value='subscribe' img src='/images/subscribe.gif' border='0' vspace='3' ></center></form><form name="Search" method="GET" action="http://search.earthweb.com/search97/search_redir.cgi"><INPUT TYPE="hidden" NAME="Action" VALUE="Search"><INPUT TYPE="hidden" NAME="SearchPage" VALUE="http://search.earthweb.com/search97/samples/forms/srchdemo.htm"><INPUT TYPE="hidden" NAME="Collection" VALUE="Site Index"><INPUT TYPE="hidden" NAME="ResultTemplate" VALUE="itl.hts"><INPUT TYPE="hidden" NAME="ViewTemplate" VALUE="view.hts"></font><table width=130 border=0 cellpadding=0 cellspacing=0><tr><td><font face="arial, helvetica" size=2 color="white"><b>Search the site:</b></font><br><INPUT NAME="queryText" size=8 VALUE=""> <input type="submit" name="submitbutton" value="Go!"></td></tr><INPUT type=hidden NAME="section_on" VALUE="on"><tr><td><SELECT NAME="section" size=1><option value="../../../../www.itlibrary.com/default.htm" SELECTED>ITLibrary<option value="../../../../www.itknowledge.com/default.htm">ITKnowledge</SELECT><a href="http://www.itlibrary.com/search/"><font face="arial, helvetica" color=FFFFFF size=1>EXPERT SEARCH</a></font><IMG src="../../../images/rule.gif" width="100" vspace=3 height="2" ALT="-----"></form></td></tr></table><table bgcolor="#cc9900" cellpadding="0" cellspacing="0" border="0" width=110><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><b><a href="http://www.itlibrary.com/reference/dir.programminglanguages.html"><font face="verdana,helvetica" size="1" color="000000">Programming Languages</font></a></b></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=12 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.databases.html"><font face="verdana,helvetica" size="1" color="000000"><b>Databases</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=12 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.security1.html"><font face="verdana,helvetica" size="1" color="000000"><b>Security</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=12 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.webservices.html"><font face="verdana,helvetica" size="1" color="000000"><b>Web Services</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=12 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.networkservices1.html"><font face="verdana,helvetica" size="1" color="000000"><b>Network Services</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=12 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.middleware.html"><font face="verdana,helvetica" size="1" color="000000"><b>Middleware</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=12 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.components.html"><font face="verdana,helvetica" size="1" color="000000"><b>Components</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=6 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.operatingsystems.html"><font face="verdana,helvetica" size="1" color="000000"><b>Operating Systems</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=6 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.userinterfaces.html"><font face="verdana,helvetica" size="1" color="000000"><b>User Interfaces</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=6 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.groupwareandcollaboration1.html"><font face="verdana,helvetica" size="1" color="000000"><b>Groupware & Collaboration</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=6 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.contentmanagement.html"><font face="verdana,helvetica" size="1" color="000000"><b>Content Management</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=6 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.productivityapplications1.html"><font face="verdana,helvetica" size="1" color="000000"><b>Productivity Applications</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=6 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.hardware1.html"><font face="verdana,helvetica" size="1" color="000000"><b>Hardware</b></font></td></tr><tr><td colspan="2"><img src="../../../images/dotclear.gif" width=6 height=12 alt="" border="0"></td></tr><tr><td><img src="../../../images/arrow.gif" width=10 height=17 alt="" border="0"></td><td><a href="http://www.itlibrary.com/reference/dir.funandgames1.html"><font face="verdana,helvetica" size="1" color="000000"><b>Fun & Games</b></font></td></tr></table><!-- <IMG SRC="/images/leftnav.gif" WIDTH=111 HEIGHT=404 ALT="nav" border="0" ISMAP USEMAP="#leftnav"> --><p><a href="http://www.earthweb.com/jobs/" target=new><IMG SRC="../../../images/dice-105x30.gif" WIDTH=105 HEIGHT=30 ALT="EarthWeb Direct" border="0"></a><a href="http://www.earthwebdirect.com/" target=new><IMG SRC="../../../images/earthwebdirect.gif" WIDTH=105 HEIGHT=30 ALT="EarthWeb Direct" border="0"></a><a href="http://www.fatbrain.com/home.html?from=UUX592" target=new><IMG SRC="../../../images/fatbrain.gif" WIDTH=105 HEIGHT=30 ALT="Fatbrain" border="0"></a><a href="http://auctions.earthweb.com" target=new><IMG SRC="../../../images/auctions_105x30.gif" WIDTH=105 HEIGHT=30 ALT="Auctions" border="0"></a><a href="http://www.supportsource.com" target=new><IMG SRC="../../../images/ss2000sneak2.gif" WIDTH=105 HEIGHT=30 ALT="Support Source Answers" border="0"></a><P><b><font face="verdana,helvetica" size="2">EarthWeb sites</FONT></b><br> <FONT SIZE="1"> <a href="http://www.crossnodes.com"><font face="verdana,helvetica" size="1" color="000000">Crossnodes</font></a><br> <a href="http://www.datamation.com"><font face="verdana,helvetica" size="1" color="000000">Datamation</font></a><br> <a href="http://www.developer.com"><font face="verdana,helvetica" size="1" color="000000">Developer.com</FONT></A><br> <a href="http://www.dice.com"><font face="verdana,helvetica" size="1" color="000000">DICE</font></a><br> <a href="http://www.earthweb.com"><font face="verdana,helvetica" size="1" color="000000">EarthWeb.com</font></a><br> <a href="http://www.earthwebdirect.com"><font face="verdana,helvetica" size="1" color="000000">EarthWeb Direct</font></a><br> <a href="http://www.erphub.com"><font face="verdana,helvetica" size="1" color="000000">ERP Hub</font></a><br> <a href="http://www.gamelan.com"><font face="verdana,helvetica" size="1" color="000000">Gamelan</font></a><br> <a href="http://www.gocertify.com"><font face="verdana,helvetica" size="1" color="000000">GoCertify.com</font></a><br> <a href="http://www.htmlgoodies.com"><font face="verdana,helvetica" size="1" color="000000">HTMLGoodies</font></a><br> <a href="http://www.intranetjournal.com"><font face="verdana,helvetica" size="1" color="000000">Intranet Journal</font></a><br> <a href="http://www.itknowledge.com"><font face="verdana,helvetica" size="1" color="000000">IT Knowledge</font></a><br> <a href="http://www.itlibrary.com"><font face="verdana,helvetica" size="1" color="000000">IT Library</font></a><br> <a href="http://www.javagoodies.com"><font face="verdana,helvetica" size="1" color="000000">JavaGoodies</font></a><br> <a href="http://www.jars.com"><font face="verdana,helvetica" size="1" color="000000">JARS</font></a><br> <a href="http://www.javascripts.com"><font face="verdana,helvetica" size="1" color="000000">JavaScripts.com</font></a><br> <a href="http://www.opensourceit.com"><font face="verdana,helvetica" size="1" color="000000">open source IT</font></a><br> <a href="http://www.roadcoders.com"><font face="verdana,helvetica" size="1" color="000000">RoadCoders</font></a><br> <a href="http://www.Y2Kinfo.com"><font face="verdana,helvetica" size="1" color="000000">Y2K Info</font></a></FONT></td><!--End Left Navigation column --><!-- spacer column --><TD width="40"><img src="../../../images/dotclear.gif" WIDTH="40" HEIGHT="1" border=0></TD><!--Begin Content Column --><TD VALIGN="TOP" width="500"><P><blockquote><p><b><font size="+1">16.8 How do I匲se MAP and ORDER methods to compare objects?</font></b><p><B>Problem</B><p>Oracle8 is not able to sort or compare objects in my database. How do I configure objects so that the Oracle8 server knows how to compare them?<P><B>Technique</B><p>Previous How-To抯 have used constructor methods to instantiate objects. These methods are system defined; Oracle8 creates a constructor method whenever a user defines an object type. The Oracle8 object implementation also enables users to create methods of their own. The CREATE TYPE and CREATE TYPE BODY commands define member methods; these methods are actually PL/SQL functions and procedures that developers create at object type definition time.<p>Developers define MAP and ORDER methods to define rules for Oracle8 to use to compare object types. Without these rules, the only object comparisons that Oracle8 will accept are equality conditions, which is a serious limitation in an object relational database.<p>We will again make use of object analogs of some of the familiar database objects traditionally residing in SCOTT抯 schema. This How-To, however, will also make use of MAP and ORDER methods so that Oracle8 will accept requests to sort or compare objects.<p><B>Steps</B><p><B>1.</B> Run SQL*Plus and connect as the WAITE user. Use the START command to load and execute the script CHP16_24.SQL as shown in <A HREF="image/16oht22.gif" TARGET="_blank">Figure 16.22</A>.<p>The script creates a new object type with three attributes to describe any particular department.<p><B>2.</B> Use the START command to load and execute the script CHP16_25.SQL. The script and its output appear in Listing 16.6.<p>Listing 16.6 Script CHP16_25.SQL creates and populates the EMP16 table<code><b><p>SQL> start chp16_25<p>SQL><p>SQL> CREATE TABLE emp16<p>2 (<p>3 empno number(4),<p>4 ename varchar2(10),<p>5 job varchar2(9),<p>6 mgr number(4),<p>7 hiredate date,<p>8 sal number(10,2),<p>9 comm number(7,2),<p>10 dept dept_typ16<p>11 );<p>Table created.<p>SQL><p>SQL><p>SQL> INSERT INTO emp16<p>2 VALUES (1, 慡AL⌨️ 快捷键说明
复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?