单选题A sequence was created with the DDL statement shown below:CREATE SEQUENCE my_sequence CACHE 10 ORDER The following statements are successfully executed in sequence through separate database connections: CONNECTION1 - VALUES NEXT VALUE FOR my_sequence I

第1题：

Which of the following is a characteristic of a sequence?（）

• A、A sequence will never generate duplicate values
• B、The MAXVALUE of a sequence can be equal to the MINVALUE
• C、It is not possible to create a sequence that generates a constant since the INCREMENT value must be greater than zero
• D、When a sequence cycles back to either the MAXVALUE or MINVALUE, it will always be equal to the specified value of either of these two boundaries

第2题：

A sequence was created with the DDL statement shown below:CREATE SEQUENCE my_sequence CACHE 10 ORDER The following statements are successfully executed in sequence through separate database connections: CONNECTION1 - VALUES NEXT VALUE FOR my_sequence INTO :con1hvar CONNECTION2 - VALUES NEXT VALUE FOR my_sequence INTO :con2hvar CONNECTION1 - VALUES NEXT VALUE FOR my_sequence INTO:con1hvarWhat is the current value of the :con1hvar host variable?（）

• A、2
• B、3
• C、11
• D、30

第3题：

What is true about sequences? （）

• A、Once created, a sequence belongs to a specific schema.
• B、Once created, a sequence is linked to a specific table.
• C、Once created, a sequence is automatically available to all users.
• D、Only the DBA can control which sequence is used by a certain table.
• E、Once created, a sequence is automatically used in all INSERT and UPDATE statements.

第4题：

Your Oracle10g database contains a table with a TIMESTAMP TO LOCAL TIME ZONE column. There are about two hundred column values for the column. You issued the following statement：   SQL> ALTER DATABASE SET TIME_ZONE =’Europe/London’；   What will be the result of issuing the above statement？（）

• A、 The statement will be executed successfully， and a new time zone will be set for the database.
• B、 The statement will be executed successfully， but a new time zone will not be set for the database.
• C、 The statement will not be executed successfully because the SET TIME_ZONE clause can be used only with the ALTER SESSION statement.
• D、 The statement will not be executed successfully because the ALTER DATABASE SET TIME_ZONE statement is used only when the database contains no table with the TIMESTAMP TO LOCAL TIME ZONE column.

第5题：

Which two statements about sequences are true? （）

• A、You use a NEXTVAL pseudo column to look at the next possible value that would be generated from a sequence, without actually retrieving the value.
• B、You use a CURRVAL pseudo column to look at the current value just generated from a sequence, without affecting the further values to be generated from the sequence.
• C、You use a NEXTVAL pseudo column to obtain the next possible value from a sequence by actually retrieving the value from the sequence.
• D、You use a CURRVAL pseudo column to generate a value from a sequence that would be used for a specified database column.
• E、If a sequence starting from a value 100 and incremented by 1 is used by more then one application, then all of these applications could have a value of 105 assigned to their column whose value is being generated by the sequence.
• F、You use REUSE clause when creating a sequence to restart the sequence once it generates the maximum value defined for the sequence.

第6题：

You created the ORDERS table in your database by using the following code：   SQL> CREATE TABLE ORDERS （ORDER_DATE TIMESTAMP（0） WITH TIME ZONE）；   Then， you inserted data in the ORDERS table and saved it by issuing the following statements：SQL> INSERT INTO ORDERS VALUES（’18-AUG-00 10：26：44 PM America/New_York’）；   SQL> INSERT INTO ORDERS VALUES（’23-AUG-02 12：46：34 PM America/New_York’）；   SQL> COMMIT；   Next， you issued the following statement to change the time zone for the database：   SQL> ALTER DATABASE SET TIME_ZONE=’Europe/London’；   What will be the result of executing the above statement？（）  

• A、 The statement will fail.
• B、 The statement will be executed successfully， and the new time zone will be set for the database.
• C、 The statement will be executed successfully， but the new time zone will be set for the current session.
• D、The statement will be executed successfully， but the new time zone will neither be set for the database nor for a specific session.

第7题：

You are developing an ASP.NET Web page that will display the median value from a sequence of integer values. You need to create an extension method to compute the median value. Which interface should you add the extension method to？（）

• A、 IComparer<T>
• B、 IEnumerable<T>
• C、 IEnumerator<T>  
• D、 IEqualityComparer<T>

第8题：

第9题：

第10题：

第11题：

第12题：

第13题：

Within the application MY_APP the following PREVIOUS VALUE expression references the sequence MY_SEQ: PREVIOUS VALUE FOR my_seq After which of the following events will the most recently generated value of MY_SEQ persist so that it can be returned to the active MY_APP application?（）

• A、After a ROLLBACK is issued
• B、After the sequence is altered
• C、After the sequence is dropped
• D、After the current session ends

第14题：

A sequence was created with the DDL statement shown below:CREATE SEQUENCE my_seq START WITH 5 INCREMENT BY 5 CACHE 5 User1 successfully executes the following statements in Connection1: VALUES NEXT VALUE FOR my_seq INTO :con1hvar VALUES NEXT VALUE FOR my_seq INTO :con1hvar User2 successfully executes the following statement in Connection2: VALUES NEXT VALUE FOR my_seq INTO :con2hvar After User1 & User2 are finished, User3 executes the following statement in Connection3: SELECT NEXT VALUE FOR my_seq FROM sysibm.sysdummy1Which value will be returned by the query?（）

• A、20
• B、25
• C、50
• D、55

第15题：

Which of the following can be used in conjunction with a Flashback Versions Query to filter the results？（）

• A、 A range of SCN values
• B、 A list of SCN values
• C、 A starting and ending timestamp
• D、 Minimum and maximum sequence values
• E、 A list of sequence values

第16题：

Your database operates in ARCHIVELOG mode. The redo log files are not multiplexed and one of the online redo logs is missing. The missing redo log sequence， 230， is not archived， and it contained information from 10：35 a.m. onwards.  The current time is 11：00 a.m. Because of a disk crash， you executed the following command to perform an incomplete recovery：  RMAN> RUN {  2> SET UNTIL SEQUENCE 230 THREAD 1;  3> ALTER DATABASE MOUNT;  4> RESTORE DATABASE;  5> RECOVER DATABASE;  6> ALTER DATABASE OPEN RESETLOGS; 7> };  With reference to this scenario， which statement is true？（）

• A、RMAN recovers up to log sequence 230， but not including 230.
• B、RMAN returns an error because the log sequence number mentioned in the command should be 229.
• C、RMAN returns an error because the log sequence number mentioned in the command may never be missing.
• D、RMAN recovers up to and including log sequence 229 but then returns an error because log sequence 230 is missing.

第17题：

What is true about sequences? （）

• A、The start value of the sequence is always 1.
• B、A sequence always increments by 1.
• C、The minimum value of an ascending sequence defaults to 1.
• D、The maximum value of descending sequence defaults to 1.

第18题：

Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2(30) JOB_ID NUMBER SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS table You created a sequence called EMP_ID_SEQ in order to populate sequential values for the EMPLOYEE_ID column of the EMPLOYEES table. Which two statements regarding the EMP_ID_SEQ sequence are true? （）

• A、You cannot use the EMP_ID_SEQ sequence to populate the JOB_ID column.
• B、The EMP_ID_SEQ sequence is invalidated when you modify the EMPLOYEE_ID column.
• C、The EMP_ID_SEQ sequence is not affected by modifications to the EMPLOYEES table.
• D、Any other column of NUMBER data type in your schema can use the EMP_ID_SEQ sequence.
• E、The EMP_ID_SEQ sequence is dropped automatically when you drop the EMPLOYEES table.
• F、The EMP_ID_SEQ sequence is dropped automatically when you drop the EMPLOYEE_ID column.

第19题：

第20题：

第21题：

第22题：

第23题：

第24题：