<ruby id="bdb3f"></ruby>

    <p id="bdb3f"><cite id="bdb3f"></cite></p>

      <p id="bdb3f"><cite id="bdb3f"><th id="bdb3f"></th></cite></p><p id="bdb3f"></p>
        <p id="bdb3f"><cite id="bdb3f"></cite></p>

          <pre id="bdb3f"></pre>
          <pre id="bdb3f"><del id="bdb3f"><thead id="bdb3f"></thead></del></pre>

          <ruby id="bdb3f"><mark id="bdb3f"></mark></ruby><ruby id="bdb3f"></ruby>
          <pre id="bdb3f"><pre id="bdb3f"><mark id="bdb3f"></mark></pre></pre><output id="bdb3f"></output><p id="bdb3f"></p><p id="bdb3f"></p>

          <pre id="bdb3f"><del id="bdb3f"><progress id="bdb3f"></progress></del></pre>

                <ruby id="bdb3f"></ruby>

                ??一站式輕松地調用各大LLM模型接口,支持GPT4、智譜、豆包、星火、月之暗面及文生圖、文生視頻 廣告
                # DBMS 中的函數依賴 > 原文: [https://beginnersbook.com/2015/04/functional-dependency-in-dbms/](https://beginnersbook.com/2015/04/functional-dependency-in-dbms/) 當表的屬性唯一地標識同一表的另一個屬性時,表的屬性被認為是彼此依賴的。 例如:假設我們有一個包含屬性的學生表:`Stu_Id`,`Stu_Name`,`Stu_Age`。這里`Stu_Id`屬性唯一地標識學生表的`Stu_Name`屬性,因為如果我們知道學生 ID,我們可以告訴與之相關的學生姓名。這被稱為函數依賴,可以寫成`Stu_Id -> Stu_Name`,或者我們可以說`Stu_Name`在函數上依賴于`Stu_Id`。 **正式**: 如果表的列`A`唯一地標識同一表的列`B`,那么它可以表示為`A -> B`(屬性`B`在函數上依賴于屬性`A`)。 ### 函數依賴的類型 * [平凡的函數依賴](https://beginnersbook.com/2015/04/trivial-functional-dependency-in-dbms/) * [非平凡的函數依賴](https://beginnersbook.com/2015/04/non-trivial-functional-dependency-in-dbms/) * [多值依賴](https://beginnersbook.com/2015/04/multivalued-dependency-in-dbms/) * [傳遞依賴](https://beginnersbook.com/2015/04/transitive-dependency-in-dbms/)
                  <ruby id="bdb3f"></ruby>

                  <p id="bdb3f"><cite id="bdb3f"></cite></p>

                    <p id="bdb3f"><cite id="bdb3f"><th id="bdb3f"></th></cite></p><p id="bdb3f"></p>
                      <p id="bdb3f"><cite id="bdb3f"></cite></p>

                        <pre id="bdb3f"></pre>
                        <pre id="bdb3f"><del id="bdb3f"><thead id="bdb3f"></thead></del></pre>

                        <ruby id="bdb3f"><mark id="bdb3f"></mark></ruby><ruby id="bdb3f"></ruby>
                        <pre id="bdb3f"><pre id="bdb3f"><mark id="bdb3f"></mark></pre></pre><output id="bdb3f"></output><p id="bdb3f"></p><p id="bdb3f"></p>

                        <pre id="bdb3f"><del id="bdb3f"><progress id="bdb3f"></progress></del></pre>

                              <ruby id="bdb3f"></ruby>

                              哎呀哎呀视频在线观看