成考院校在线答案
- 2022-09-12 [单选] <p class="MsoNormal">25、<span style="font-size:14.0pt;font-family:Microsoft Yahei;mso-ascii-font-family: "Times New Roman";mso-hansi-font-family:"Times New Roman"">下面哪个不是数据库系统必须提供的数据控制功能</span><span lang="EN-US" style="font-size:14.0pt">___</span><span style="font-size:14.0pt; font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">。</span></p>
- 2022-09-12 [单选] <p class="MsoNormal">26、<span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman"; mso-hansi-font-family:"Times New Roman"">对于学生</span><span lang="EN-US">--</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">选课</span><span lang="EN-US">--</span><span style="font-family: 宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"">课程的三个关系：</span></p> <p class="MsoNormal"><span lang="EN-US">S(S#,SNAME,SEX,AGE)</span></p> <p class="MsoNormal"><span lang="EN-US">SC(S#,C#,GRADE)</span></p> <p class="MsoNormal"><span lang="EN-US">C(C#,CNAME,TEACHER)</span></p> <p class="MsoNormal"><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman"; mso-hansi-font-family:"Times New Roman"">为了提高查询速度，对</span><span lang="EN-US">SC</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">表创建唯一索引，应建</span><span lang="EN-US">___</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">个组上。</span></p>
- 2022-09-12 [单选] <p class="MsoNormal" style="mso-pagination:widow-orphan">31、<span lang="EN-US">SQL</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">语句执行的结果是</span><span lang="EN-US">___</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">。</span><span lang="EN-US" style="mso-bidi-font-size:10.5pt; mso-font-kerning:0pt"> <o:p></o:p></span></p>
- 2022-09-12 [单选] <p class="MsoNormal" style="mso-pagination:widow-orphan">38、<span lang="EN-US">SQL</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">语言的数据操纵句包括</span><span lang="EN-US">SELECT</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">，</span><span lang="EN-US">INSERT</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">，</span><span lang="EN-US">UPDATE</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">和</span><span lang="EN-US">DELETE</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">，最重要的，也是使用最频繁的语句是</span><span lang="EN-US">___</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">。</span><span lang="EN-US" style="mso-bidi-font-size:10.5pt; mso-font-kerning:0pt"> <o:p></o:p></span></p>
- 2022-09-12 [判断] <p class="MsoNormal" style="mso-pagination:widow-orphan">26、<span style="mso-bidi-font-size:10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman"; mso-hansi-font-family:"Times New Roman"">一个语言的文法是唯一的。</span><span lang="EN-US" style="mso-bidi-font-size:10.5pt;mso-font-kerning:0pt"> <o:p></o:p></span></p>
- 2022-09-12 [判断] <p class="MsoNormal" style="mso-pagination:widow-orphan">25、<span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">语法分析时必须先消除文法中的左递归。</span><span lang="EN-US" style="mso-bidi-font-size:10.5pt;mso-font-kerning:0pt"> <o:p></o:p></span></p>
- 2022-09-12 [判断] <p class="MsoNormal" style="mso-pagination:widow-orphan">24、<span style="mso-bidi-font-size:10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman"; mso-hansi-font-family:"Times New Roman"">若两个正规式所表示的正规集相同，则认为二者是等价的。</span><span lang="EN-US" style="mso-bidi-font-size:10.5pt;mso-font-kerning:0pt"> <o:p></o:p></span></p>
- 2022-09-12 [判断] <p class="MsoNormal" style="mso-pagination:widow-orphan">38、<span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">对中间代码的优化依赖于具体的计算机。</span><span lang="EN-US" style="mso-bidi-font-size:10.5pt;mso-font-kerning:0pt"> <o:p></o:p></span></p>
- 2022-09-12 [判断] <p class="MsoPlainText" style="line-height:18.0pt;mso-pagination:widow-orphan">35、<span style="mso-bidi-font-size:10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman"">如果一个文法存在某个句子对应两棵不同的语法树，则文法是二义性的。</span><span lang="EN-US" style="mso-bidi-font-size:10.5pt;mso-font-kerning:0pt"> <o:p></o:p></span></p>
- 2022-09-12 [判断] <p class="MsoNormal" style="mso-pagination:widow-orphan">37、<span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">设有一个</span><span lang="EN-US">LR</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">（</span><span lang="EN-US">0</span><span style="font-family: 宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"">）项目集</span><span lang="EN-US">I</span><sub><span lang="EN-US" style="mso-bidi-font-size:10.5pt">i</span></sub><span lang="EN-US">={X→</span><span lang="EN-US" style="font-family:Microsoft Yahei;mso-ascii-font-family: "Times New Roman"">α</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family: "Times New Roman";mso-hansi-font-family:"Times New Roman"">．</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman"">，</span><span lang="EN-US" style="mso-hansi-font-family:宋体">A</span><span lang="EN-US">→</span><span lang="EN-US" style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman"">α</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">．</span><span lang="EN-US">}</span><span style="font-family: 宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"">，该项目集含有</span><span lang="EN-US">“</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman"; mso-hansi-font-family:"Times New Roman"">归约</span><span lang="EN-US">-</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">归约冲突</span><span lang="EN-US">”</span><span style="font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family: "Times New Roman"">。</span><span lang="EN-US" style="mso-bidi-font-size:10.5pt; mso-font-kerning:0pt"> <o:p></o:p></span></p>