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「MYSQL學習心得」目錄
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1. 何謂VIEW
xoops中使用預存程序
1. 何謂VIEW
1-1 建立、刪除觀點 (View)
1-2 CREATE VIEW: 建立一個新的觀點
1-3 DROP VIEW: 刪除一個觀點
1-4 View的優缺點
1-5 練習
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1-2 CREATE VIEW: 建立一個新的觀點
MYSQL學習心得 ========= - <span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:24.0pt;">觀點 </span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:24.0pt;">(View):</span></span></span> <div style="margin-left:.79in;"><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">不以實體表格的形式存在，可視為一個</span></span></span><span style="color:red;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">虛擬表格</span></span></span></div><div style="margin-left:.79in;"><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">其內容是</span></span></span><u><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">以</span></span></span></u><u><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">SELECT</span></span></span></u><u><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">指令的執行結果</span></span></span></u><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">構成，所以其定義方式正是以</span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">SELECT</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">為基礎</span></span></span></div>- <span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:24.0pt;">在</span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:24.0pt;">MySQL</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:24.0pt;">中，</span></span></span> <div style="margin-left:.79in;"><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">可使用</span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">SQL</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">標準語法 </span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">(</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">即：</span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">CREATE VIEW) </span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">來建構 </span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">view</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">。</span></span></span></div><div style="margin-left:.79in;"><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">利用</span></span></span><span style="color:red;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">show tables</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">，可以看到</span></span></span><u><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">所建立出來的</span></span></span></u><u><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">view</span></span></span></u><u><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">和其它的表格是放在一起的，就像是一個真正的表格一樣，只是它是屬於虛擬表格</span></span></span></u><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">。</span></span></span></div><div style="margin-left:.79in;"><span style="font-size:20.0pt;"><span style="font-size:65%;"><span style="font-family:wingdings;"><span style="color:#999933;">¡</span></span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">正是因為它是虛擬表格，所以不能使用</span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">DROP TABLE</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">來刪除它</span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">!! </span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">可使用</span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">SQL</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">標準語法的</span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">DROP VIEW</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">來刪除一個</span></span></span><span style="color:#292929;"><span style="font-family:rockwell condensed;"><span style="font-size:20.0pt;">view</span></span></span><span style="color:#292929;"><span style="font-family:ms pgothic;"><span style="font-size:20.0pt;">。</span></span></span></div>
1. 何謂VIEW