多选题Given:
2. interface Machine { }
3. interface Engine { }
4. abstract interface Tractor extends Machine, Engine {
5. void pullStuff();
6. }
7. class Deere implements Tractor {
8. public void pullStuff() {System.out.print("pulling "); }
9. }
10. class LT255 implements Tractor extends Deere {
11. public void pullStuff() {System.out.print("pulling harder "); }
12. }
13. public class LTI55 extends Deere implements Tractor, Engine { }
What is the result? (Choose all that apply.)
多选题如果要显示库存超过100的所有产品(product)的产品标识号(id_number)，并且想以这样的方式来显示：首先以制造商(manufacturer)的字母顺序，之后按产品号由小到大的顺序，应该使用如下的哪个语句来完成这一工作?注意所有的数据也都存放在INVENTORY表中。
多选题使用DELETE FROM service;语句，可完成如下哪个任务? A．删除service表 B．删除service列 C．删除service表中所有的行 D．删除所有没有NOTNULL约束的列中的值
多选题为什么不在CLASS SCHEDULE表中的一列上创建索引?
多选题请检查如下的查询语句：
SELECT order_num,
在以下有关执行这个SQL语句的陈述中，哪一个是正确的?
多选题应该在哪一列上创建一个索引?
多选题哪些语句正确描述了级别0增量备份?
多选题Given that:
Exception is the superclass of IOException, and
IOException is the superclass of FileNotFoundException, and
3. import java.io.*;
4. class Physicist {
5. void think() throws IOException { }
6. }
7. public class Feynman extends Physicist {
8. public static void main(String[] args) {
9. new Feynman().think();
10. }
11. // insert method here
12. }
Which of the following methods, inserted independently at line 11, compiles? (Choose all that apply.)
多选题以下是CLASSES和SCHEDULE表的结构(所包含的列及列的定义)： CLASSES --------- ID NUMBER(9) CLASS_NAME VARCHAR2(20) TEACHER_ID NUMBER(9) SCHEDULE ------------ CLASS_TIME DATE CLASS_ID NUMBER(9) 如需要创建一个视图，而这个视图将显示每节课的上课时间(class time)、课程名(class name)并按教师id (teacher id)的顺序排序。使用了如下的语句，请问这一语句将提供哪一个结果? CREATE VIEW class_schedule AS SELECT c.class_name, s.class_time FROM classes c, schedule s WHERE c.id=s.class_id; A．该语句将创建视图CLASS_SCHEDULE并取得所希望的结果 B．该语句将创建视图CLASS_SCHEDULE，但是不能获取所希望的结果 C．该语句将返回一个语法错误，因为创建视图(Create View)语句不能基于连接查询(Join Query) D．该语句将返回一个语法错误，因为创建视图(Create View)语句没有包含ORDER BY子句
多选题使用哪个字符函数来返回一个值中字符的个数?
多选题Given:
1. class MyClass { }
And given that MyClass2 has properly overridden equals() and hashCode() objects from which classes make good hashing keys? (Choose all that apply.)
多选题RMAN RUN块中包含以下两个命令：
set newname for datafile "/u01/oradata/dw/users04.dbf"
to"/u06/oradata/dw/users04.dbf";
restore tablespace users;
如果运行此RESTORE命令，会产生什么结果?
多选题Given:
2. public class Payroll {
3. int salary;
4. int getSalary() {return salary; }
5. void setSalary(int s) {
6. assert(s ＞ 30000);
7. salary = s;
8. } }
Which are true? (Choose all that apply.)
多选题Given:
2. class Car {
3. private Car() { }
4. protected Car(int x) { }
5. }
6. public class MG extends Car {
7. // MG(int x) { }
8. // MG(int x) {super(); }
9. // MG(int x) {super(x); }
10. // private MG(int x) {super(x); }
11. // MG() { }
12. // MG() {this(); }
13. // MG() {this(6); }
14. // MG() {super(7); }
15. public static void main(String[] args) {
16. new MG(7);
17. new MG();
18. } }
Which sets of constructors can be uncommented for the code to compile? (Choose all that apply.)
多选题数据库管理员使用了“ALTER INDEX babydog DEALLOCATE UNUSED;”，请问这个DDL，语句的作用是什么? A．截断babydog索引 B．回收babydog索引所使用的全部磁盘空间 C．释放在babydog索引中所有没有使用的磁盘空间 D．释放在babydog索引中高水线之上所有没有使用的磁盘空间
多选题Given:
2. class Pancake { }
3. class BlueberryPancake extends Pancake { }
4. public class SourdoughBlueberryPancake2 extends BlueberryPancake {
5. public static void main(String[] args) {
6. Pancake p4 = new SourdoughBlueberryPancake2();
7. // insert code here
8. } }
And the following six declarations (which are to be inserted independently at line 7):
Ⅰ. Pancake p5 = p4;
Ⅱ. Pancake p6 = (BlueberryPancake)p4;
Ⅲ. BlueberryPancake b2 = (BlueberryPancake)p4;
Ⅳ. BlueberryPancake b3 = (SourdoughBlueberryPancake2)p4;
Ⅴ. SourdoughBlueberryPancake2 s1 = (BlueberryPancake)p4;
Ⅵ. SourdoughBlueberryPancake2 s2 = (SourdoughBlueberryPancake2)p4;
Which are true? (Choose all that apply.)
多选题Which statement(s) are true? (Choose all that apply.)
多选题以下哪个命令将造成事务的隐式提交?
多选题Given:
1. class Contact {
2. String doStuff() {return "howdy "; }
3. }
4. class Supplier extends Contact {
5. String doStuff() {return "send money "; }
6. public static void main(String[] args) {
7. Supplier s1 = new Supplier();
8. Contact c3 = new Contact();
9. Contact c1 = s1;
10. Supplier s2 = (Supplier) c1;
11. Supplier s3 = (Supplier) c3;
12. Supplier s4 = new Contact();
13. } }
Which are true? (Choose all that apply.)
A. Compilation succeeds.
B. The code runs without exception.
C. If the line(s) of code that do NOT compile (if any) are removed, the code runs without exception.
D. If the line(s) of code that do NOT compile (if any) are removed, the code throws an exception at runtime.
多选题下面哪条语句正确描述了Flashback Data Archive?