The EMP table contains these columns: EMPLOYEE_ID NUMBER(4) EMPNAME VARCHAR2 (25) SALARY NUMBER(9,2) HIRE_DATE DATE You query the database with this SQL statement: SELECT empname,hire_date HIREDATE, salary FROM EMP ORDER BY hire_date; How will the result

randomly

ascending by date

descending by date

ascending alphabetically

descending alphabetically

DELETE FROM EMP;

TUNCATE TABLE EMP;

TUNCATE TABLE EMP REUSE STORAGE;

DROP TABLE EMP;

以上所述都不正确

to undo the changes made to the EMP table since the specified time

to restore the EMP table that was wrongly dropped from the database

to view the transactions that have modified the EMP table since the specified time

to view the changes made to the EMP table for one or more rows since the specified time

to recover the EMP table to a point in time in the past by restoring the most recent backup

 to undo the changes made to the EMP table since the specified time

 to restore the EMP table that was wrongly dropped from the database

 to view the transactions that have modified the EMP table since the specified time

 to view the changes made to the EMP table for one or more rows since the specified time

CREATE TABLE EMP (empno NUMBER(4), ename VARCHAR2(35), deptno NUMBER(7,2) NOT NULL, CONSTRAINT emp_deptno_fk FOREIGN KEY deptno REFERENCES dept deptno);

CREATE TABLE EMP (empno NUMBER(4), ename VARCHAR2(35), deptno NUMBER(7,2) CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));

CREATE TABLE EMP (empno NUMBER(4), ename VARCHAR2(35), deptno NUMBER(7,2) NOT NULL, CONSTRAINT emp_deptno_fk REFERENCES dept (deptno) FOREIGN KEY (deptno));

CREATE TABLE EMP (empno NUMBER(4), ename VARCHAR2(35), deptno NUMBER(7,2) FOREIGN KEY CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));

 You must enable the block change tracking feature.

 You must have enable the flashback feature.

 You must use the OMF in your database.

 You must define the tablespace of the SCOTT.EMP table for automatic segment space management.

LOCK TABLE emp IN SHARE MODE;

LOCK TABLE emp IN EXCLUSIVE MODE;

DELETE FROM emp WHERE job=’MANAGER’;

INSERT INTO emp（empno，ename） VALUES （1289，’Dick’）;

SELECT job FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno;

LOCK TABLE emp IN SHARE MODE；

LOCK TABLE emp IN EXCLUSIVE MODE；

UPDATE emp SET sal=sal*1.2 WHERE job=ANAGER？UPDATE emp SET sal=sal*1.2 WHERE job=？ANAGER？

INSERT INTO emp（empno，ename） VALUES （1289，’Harry’）；

SELECT ename FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno

SELECT last_name, 12*salary* commission_pct FROM emp;

SELECT last_name, 12*salary* (commission_pct,0) FROM emp;

SELECT last_name, 12*salary*(nvl(commission_pct,0)) FROM emp;

SELECT last_name, 12*salary*(decode(commission_pct,0)) FROM emp;

 The PRIMARY KEY is created along with a new index.

 The PRIMARY KEY is created and it would use an existing unique index.

 The PRIMARY KEY would be created in a disabled state because it is using an existing index.

 The statement produces an error because the USING clause is permitted only in the CREATE TABLE command.

when the schema of the user， SCOTT， was deleted by mistake 15 minutes ago

when the table EMP of the SCOTT schema was dropped by mistake 15 minutes ago

when some rows of the table， EMP， in the SCOTT schema were deleted by mistake 15 minutes ago

when some incorrect values were inserted in the EMP table in the user Scott’s schema during the last 15 minutes

never， because FLASHBACK TABLE is not a valid command in Oracle 10g.

DELETE * FROM. EMP

DELETE FROM EMP

TRUNCATE TABLE EMP

DELETE TABLE EMP

The FLASHBACK TABLE statement will not be written to the alert log file.

The changes made to the EMP table since the specified time will be undone.

The EMP table that was dropped by mistake from the database will be restored.

The FLASHBACK TABLE statement will be executed within a single transaction.

The FLASHBACK TABLE statement will not maintain the existing indexes on the EMP table.

The list of transactions that have modified the EMP table since the specified time will be displayed.

 You must enable the row movement on the SCOTT.EMP table.

 You must define the tablespace of the SCOTT.EMP table for automatic segment space management.

 You must use the CASCADE clause in the ALTER TABLE SHRINK SPACE statement.

 You must use the COMPACT clause in the ALTER TABLE SHRINK SPACE statement.

CREATE TABLE EMP9$# AS (empid number(2));

CREATE TABLE EMP*123 AS (empid number(2));

CREATE TABLE PACKAGE AS (packid number(2));

CREATE TABLE 1EMP_TEST AS (empid number(2));

LOCK TABLE emp IN SHARE MODE；

LOCK TABLE emp IN EXCLUSIVE MODE；

UPDATE emp SET sal=sal*1.2 WHERE job=MANAGER；

INSERT INTO emp（empno，ename） VALUES （1289，’Harry’）；

SELECT ename FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno；

CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) NOT NULL CONSTRAINT emp_deptno_fk FOREIGN KEY deptno REFERENCES dept deptno);

CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) CONSTRAINT emp_deptno_fk REFERENCES dept (deptno));

CREATE TABLE EMP (empno NUMBER(4) ename VARCHAR2(35), deptno NUMBER(7,2) NOT NULL, CONSTRAINT emp_deptno_fk REFERENCES dept (deptno) FOREIGN KEY (deptno));

CREATE TABLE EMP (empno NUMBER(4), ename VARCNAR2(35), deptno NUMBER(7,2) FOREIGN KEY CONSTRAINT emp deptno fk REFERENCES dept (deptno));

Exhibit A

Exhibit B 

The query returns no rows 

The query fails because the outer query is retrieving more than one column

The query fails because both the inner and outer queries are retrieving data from the same table.