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?
多选题如果Duck数据库有4组重做日志，并且每一组有3个成员，Oracle将推荐使用多少个硬盘来维护这些重做日志文件? A．3 B．4 C．6 D．8 E．12
多选题Given:
1. import java.io.*;
2. public class Edgy {
3. public static void main(String[] args){
4. try {
5. wow();
6. // throw new IOException();
7. } finally {
8. // throw new Error();
9. // throw new IOException();
10. }
11. }
12. static void wow() {
13. // throw new IllegalArgumentException();
14. // throw new IOException();
15. } }
And given that IOException is a direct subclass of java.lang.Exception, and that llegalArgumentException is a runtime exception, which of the following, if uncommented independently, will compile? (Choose all that apply.)
多选题Given:
2. public class Buffalo {
3. static int x;
4. int y;
5. public static int getX() {return x; }
6. public static void setX(int newX) {x = newX; }
7. public int getY() {return y; }
8. public void setY(int newY) {y = newY; }
9. }
Which lines of code need to be changed to make the class thread safe? (Choose all that apply.)
多选题Given:
2. public class Boot {
3. static String s;
4. static {s = "" ; }
5. {System.out.print("shinier "); }
6. static {System.out.print(s.concat("better ")); }
7. Boot() {System.out.print(s.concat("bigger ")); }
8. public static void main(String[] args) {
9. new Boot();
10. System.out.println("boot");
11. } }
What is the result?
多选题Given that the current directory is bigApp, and the following directory structure:
bigApp
|-- classes
|-- source
|-- com
|-- wickedlysmart
|-- BigAppClassl.java
And the code:
package com.wickedlysmart;
public class BigAppClassl {
int doStuff() {return 42; }
}
And the following command-line invocations:
Ⅰ. javac -d source/com/wickedlysmart/BigAppClassl.java
Ⅱ. javac -d classes source/com/wickedlysmart/BigAppClassl.java
Ⅲ. javac -d classes/com/wickedlysmartsource/com/wickedlysmart/BigAppClassl.java
Which are true? (Choose all that apply.)
多选题Given:
2. public class Pregnant extends Thread {
3. int x = 0;
4. public static void main(String[] args) {
5. Runnable r1 = new Pregnant();
6. new Thread(r1) .start();
7. new Thread(r1) .start();
8. }
9. public void run() {
10. for(int j = 0; j ＜ 3; j++) {
11. x = x + 1;
12. x = x + 10;
13. System.out.println(x + " ");
14. x = x + 100;
15. } } }
If the code compiles, which value(s) could appear in the output? (Choose all that apply.)
多选题如要关闭资源限制，应该修改如下的哪一个初始化参数? A．PROCESSES B．SESSION_LIMIT C．RESOURCE_LIMIT D．TIMED_STATISTICS
多选题使用分组函数可完成以下的哪个操作? A．以‘DD MON YYYY’的格式显示订单(orders)的订货日期(order date) B．将字符串‘January 23 2010’转换成日期格式 C．产生PRODUCT表中COST列所有值的总和 D．以小写字母的形式显示PRODUCT表中DESCRIPTION列所有的值
多选题Given:
3. public class Chopper {
4. String a = "12b";
5. public static void main(String[] args) {
6. System.out.println (new Chopper().chop(args[0]));
7. }
8. int chop(String a) {
9. if(a == null) throw new IllegalArgumentException();
10. return Integer.parseInt(a);
11. } }
And, if the code compiles, the invocation:
java Chopper
What is the result?
多选题以下哪个SQL命令将删除视图PARTS_VU?
多选题假设正在计划数据库的配置，那么应该如何组织数据的存储? A．应该将具有不同备份需求的对象组织在一起 B．应该将具有I/O竞争需求的对象组织在一起 C．应该将具有不同生命期的对象分开存放以最小化碎片问题 D．应该将具有静态特性的对象分开存放
多选题评估如下的SQL*Plus命令：
SPOOL dog.1st
这一SQL*Plus命令将产生哪个结果?
多选题在以下有关Oracle约束的陈述中，哪4个是正确的? A．条件约束说明一个必须成立的条件 B．主键约束唯一地标识一个表中的每一行 C．非空(NOT NULL)约束确保在一列中不允许有空值(NULL) D．唯一约束防止输入空值，因为空值对这一约束不安全 E．唯一约束说明对一个表中所有的数据行的一列或几列的组合必须是唯一的 F．当一列是唯一标识每一行的一部分时，主键约束允许这一列可以出现空值
多选题下面哪些描述是使用恢复目录替代目标数据库控制文件的正当理由。
多选题下面哪些初始化参数无效?
多选题在以下的命令中，应该使用哪一个来激活(开启)一个角色? A．SET ROLE B．ALTER USER C．CREATE ROLE D．ALTER SYSTEM