n层设计基础续.htm

UML软件工程组织面向对象实例文档 内涵GIF 图片和网络文件格式

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style="FONT-SIZE: 12pt; LETTER-SPACING: 0.3pt; mso-bidi-font-size: 10.0pt; mso-fareast-language: ZH-CN">&nbsp;<O:P> 
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<P class=MsoNormal><SPAN lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN; mso-spacerun: yes">&nbsp;&nbsp;&nbsp; 
</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">在上图</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">2</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">里﹐只有一个企业对象</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">-----Account</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">对象，此时您当然可以举一反三，而认知到：可以有很多个企业对象，而且都是</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">stateful</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的对象。</SPAN><SPAN 
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<P class=MsoNormal><SPAN lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN; mso-spacerun: yes">&nbsp;&nbsp;&nbsp; 
</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">例如，要存取数据库里的另一个表格──</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">Customer</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">表格﹐则可以定义一个</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">CustPersist</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">类别协助存取</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">Customer</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">表格，并定义一个</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">Customer</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">类别来含纳企业规则。</SPAN><SPAN 
lang=EN-US style="LETTER-SPACING: 0.3pt"><O:P> </O:P></SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US style="LETTER-SPACING: 0.3pt">&nbsp;<O:P> 
</O:P></SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US style="LETTER-SPACING: 0.3pt"><!--[if gte vml 1]><V:SHAPE id=_x0000_i1027 
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</SPAN><I style="mso-bidi-font-style: normal"><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">图</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">3</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、模式</SPAN><SPAN 
lang=EN-US 
style="FONT-FAMILY: Monotype Sorts; LETTER-SPACING: 0.3pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman; mso-char-type: symbol; mso-symbol-font-family: Monotype Sorts">&raquo;</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN"> 
----</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">存取两个</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">DB</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">表格</SPAN></I><SPAN 
lang=EN-US style="LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN"><O:P> 
</O:P></SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN">&nbsp;<O:P> 
</O:P></SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN; mso-spacerun: yes">&nbsp;&nbsp;&nbsp; 
</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">如果您很欣赏<SPAN 
style="mso-font-kerning: 8.0pt">模式</SPAN></SPAN><SPAN lang=EN-US 
style="FONT-FAMILY: Monotype Sorts; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman; mso-char-type: symbol; mso-symbol-font-family: Monotype Sorts">&sup1;</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的话，应该会觉得此模式</SPAN><SPAN 
lang=EN-US 
style="FONT-FAMILY: Monotype Sorts; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman; mso-char-type: symbol; mso-symbol-font-family: Monotype Sorts">&raquo;</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的是很自然而美好的。反之，如果您很习惯于使用</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN">MTS</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN">SPM(shared 
property manager)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的话，您可能会觉得多定义了</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN">Account</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN">Customer</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等类别，实在吃饱没事干的人才会如此做！</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN"><O:P> 
</O:P></SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-spacerun: yes">&nbsp;&nbsp;&nbsp; 
</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">此外，如果您很熟悉传统</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN">2-tier</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">架构的话，您会觉得</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN">Account</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
lang=EN-US 
style="mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">Customer</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等类别是多余的，这些类别里的企业规则</SPAN><SPAN 
lang=EN-US 
style="mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">(business 
rule)</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">可以写在</SPAN><SPAN 
lang=EN-US 
style="mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">Form</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">里就行了。</SPAN></P>
<P class=MsoNormal style="MARGIN-BOTTOM: 6pt"><SPAN lang=EN-US 
style="mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN; mso-spacerun: yes">&nbsp;&nbsp;&nbsp; 
</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">因此，这个<SPAN 
style="LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt">模式</SPAN></SPAN><SPAN 
lang=EN-US 
style="FONT-FAMILY: Monotype Sorts; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman; mso-char-type: symbol; mso-symbol-font-family: Monotype Sorts">&raquo;</SPAN><SPAN 
style="FONT-FAMILY: 宋体; LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的最大弱点是：大多数的人会觉得</SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN">Account</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
lang=EN-US 
style="mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">Customer</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等类别是多余的，而且增加程序设计者的限制，实在碍手碍脚的。<SPAN 
style="LETTER-SPACING: 0.3pt; mso-font-kerning: 8.0pt">然而有些人就能轻易看出</SPAN></SPAN><SPAN 
lang=EN-US 
style="LETTER-SPACING: 0.3pt; mso-fareast-font-family: 宋体; mso-font-kerning: 8.0pt; mso-fareast-language: ZH-CN">Account</SPAN><SPAN 
style="FONT-FAMILY: 宋体; mso-fareast-language: ZH-CN; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN 
lang=EN-US 
style="mso-fareast-font-family: 宋体; mso-fareast-language: ZH-CN">Customer</SPAN><SPAN