题目内容
（请给出正确答案）
[主观题]
当where条件中存在unique或者primary key的情况下，并且返回单个rowid数据内容时，Oracle将使用哪种扫描（)
A、Index range scan
B、Index fast full scan
C、Index unique scan
D、Index full scan
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A.4
B.3
C.1
D.0
更多“当where条件中存在unique或者primary key…”相关的问题
第1题
The following statements:CREATE TABLE t1 (col1 INT NOT NULL, PRIMARY KEY(col1)); CREATE TABLE t2 (col1 INT NOT NULL, col2 CHAR(1) NOT NULL, PRIMARY KEY (col1, col2), FOREIGN KEY (col1) REFERENCES t1 (col1) ON DELETE CASCADE ON UPDATE RESTRICT); CREATE TABLE t3 (col1 INT NOT NULL, col2 INT NOT NULL, PRIMARY KEY (col1, col2),FOREIGN KEY (col1) REFERENCES t1 (col1) ON DELETE NO ACTION ON UPDATE RESTRICT);INSERT INTO t1 VALUES (1), (2); INSERT INTO t2 VALUES (1, ‘a‘), (1, ‘b‘), (2,‘c‘); INSERT INTO t3 VALUES (1, 100), (2, 200), (2,300);How many rows will be deleted by the following DELETE statement? DELETE FROM t1 WHERE col1= 1;（）
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第2题
Examine the structure of the STUDENTS table:STUDENT_ID NUMBER NOT NULL, Primary KeySTUDENT_NAME VARCHAR2(30)COURSE_ID VARCHAR2(10) NOT NULLMARKS NUMBERSTART_DATE DATEFINISH_DATE DATEYou need to create a report of the 10 students who achieved the highest ranking in the course INT SQL and who completed the course in the year 1999.Which SQL statement accomplishes this task? （）
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A. SELECT student_ id, marks, ROWNUM "Rank" FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN ‘01-JAN-99‘ AND ‘31-DEC-99 AND course_id = ‘INT_SQL‘ ORDER BY mark DESC;
B. SELECT student_id, marks, ROWID "Rank" FROM students WHERE ROWID <= 10 AND finish_date BETWEEN ‘01-JAN-99‘ AND ‘31-DEC-99‘ AND course_id = ‘INT_SQL‘ ORDER BY mark;
C. SELECT student_id, marks, ROWNUM "Rank" FROM (SELECT student_id, marks FROM students WHERE ROWNUM <= 10 AND finish_date BETWEEN ‘01-JAN-99‘ AND ‘31-DEC- 99‘ AND course_id = ‘INT_SQL‘ ORDER BY mark DESC;
D. SELECT student_id, marks, ROWNUM "Rank" FROM (SELECT student_id, marks FROM students WHERE (finish_date BETWEEN ‘01-JAN-99 AND ‘31-DEC-99‘ AND course_id = ‘INT_SQL‘ ORDER BY marks DESC) WHERE ROWNUM <= 10;
E. SELECT student id, marks, ROWNUM "Rank" FROM (SELECT student_id, marks FROM students ORDER BY marks) WHERE ROWNUM <= 10 AND finish date BETWEEN ‘01-JAN-99‘ AND ‘31-DEC-99‘ AND course _ id ‘INT_SQL‘;
第4题
DateGrid的哪个属性可以显示列表的行号()
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A、displayRowNumber
B、allowRowNumber
C、displayPrimaryKey
D、allowPrimaryKey
第5题
Examinethecommand：ALTERDATABASEADDSUPPLEMENTALLOGDATA（PRIMARYKEY）COLUMNS；Whatdoesthecommandaccomplish？（）
A.Createsanadditionalcopyofthedatabaseonlineredologfiles.
B.StorestheprimarykeycolumnvaluesofeachrowinvolvedinaDMLoperationintheonlineredologfiles.
C.StorestheprimarykeycolumnvaluesofeachrowinvolvedinaDMLoperationinthesupplementallogfiles.
D.StorestheoldandnewprimarykeycolumnvaluesofeachrowinvolvedinaDMLoperationonlywhentheprimarykeyismodifiedintheonlineredologfiles.
第6题
考生文件夹下存在一个数据库文件“samp3．mdb”，里面已经设计好表对象“tBorrow”、“treader”和“tBook”，查询对象“qT”，窗体对象“fReader”、报表对象“rReader”和宏对象“rpt”。请在此基础上按照以下要求补充设计：
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(1)在报表“rReader”的报表页眉节区内添加一个标签控件，其名称为“bTitle”，标题显示为“读者借阅情况浏览”，字体名称为“黑体”，字号大小为22，同时将其安排在距上边0．5厘米、距左侧2厘米的位置。
(2)设计报表“rReader”的主体节区为“tSex”文本框控件设置数据来源显示性别信息，并要求按“借书日期”字段升序显示，“借书日期”的显示格式为“长日期”的形式。
(3)将宏对象“rpt”改名为“mReader”。
(4)在窗体对象“treader”的窗体页脚节区内添加一个命令按钮，命名为“bList”，按钮标题为“显示借书信息”，其单击事件属性设置为宏对象“mReader”。
(5)窗体加载时设置窗体标题属性为系统当前日期。窗体“加载”事件代码已提供，请补充完整。
注意：不允许修改窗体对象“treader”中未涉及的控件和属性；不允许修改表对象“tBorrow”、“tReader”和“tBook”及查询对象“qT”：不允许修改报表对象“tReader”的控件和属性。
程序代码只允许在“*****Add*****”与“*****Add*****”之间的空行内补充一行语句、完成设计，不允许增删和修改其他位置已存在的语句。
第7题
A．She almost forgets to give the key to Professor Brown.
B．She almost forgets to tell where the classroom is.
C．She almost forgets to tell professor the exact time of the class.
D．She almost forgets to tell professor to assign the new exercise.
第8题
在Oracle中，以下是STUDENTS表的结构：SIDNUMBERNOTNULL，PrimaryKeySNAMEVARCHAR2(30)COURSE_IDVARCHAR2(10)NOTNULLMARKSNUMBER你需要查询参加了课程ID为C10的考试，并且分数排在前10名的学生，以下()语句能够实现此功能。
A.SELECTSID,marks,ROWNUM“Rank”
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FORMstudents
WHEREROWNUM<=10ANDcourse_id=’C10′
ORDERBYmarksDESC;
B.SELECTSID,marks,ROWNUM”Rank”
FORMstudents
WHEREROWNUM<=10ANDcourse_id=’C10′
ORDERBYmarks;
C.SELECTSID,marks,ROWNUM”Rank”
FORM(SELECTSID,marks
FORMstudents
WHEREROWNUM<=10ANDcourse_id=’C10′
ORDERBYmarksDESC;
D.SELECTSID,marks,ROWNUM”Rank”FORM(SELECTSID,marks
FORMstudents
WHEREcourse_id=’C10′ORDERBYmarksDESC)
WHEREROWNUM<=10;
第9题
听力原文：Seven. Where are the man and the woman talking?
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Woman: It's a bit crowded isn't it ... worse than a football match! Can you see well enough from here?
Man: It doesn't matter — as long as I can hear and get down the important points of what he says, it's OK.
Woman: I'm going to the library after this. I want to get this report finished so that I can go to the cinema.
Where are the man and the woman talking?
A．
B．
C．
第10题
听力原文：Where shall we sit?
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(A) How about the front row?
(B) Before the show starts.
(C) It's on the table.
(11)
A．
B．
C．
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