单项选择题

Examine the structure of the EMPLOYEES table: EMPLOYEE_……

Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key
FIRST_NAME VARCHAR2(25)
LAST_NAME VARCHAR2(25)
HIRE_DATE DATE
You issue these statements:
CREATE table new_emp ( employe_id NUMBER, name VARCGAR2(30));
INSERT INTO new_emp SELECT employee_id, last_name from employees; Savepoint s1;
UPDATE new_emp set name = UPPER(name);
Savepoint s2;
Delete from new_emp;
Rollback to s2;
Delete from new_emp where employee_id=180;
UPDATE new_emp set name = 'James';
Rollback to s2;
UPDATE new_emp sey name = 'James' Where employee_id=180; Rollback;
At the end of this transaction, what is true? （）

A. You have no rows in the table.
B. You have an employee with the name of James.
C. You cannot roll back to the same savepoint more than once.
D. Your last update fails to update any rows because employee ID 180 was already deleted.

<上一题目录下一题>

热门试题

单项选择题Mary has a view called EMP_DEPT_LOC_VU that was created based on the EMPLOYEES,DEPARTMENTS, and LOCATIONS tables. She granted SELECT privilege to Scott on this view. Which option enables Scott to eliminate the need to qualify the view with the name MARY .EMP_DEP_LOC_VU each time the view is referenced? （）

A. Scott can create a synonym for the EMP_DEPT_LOC_VU bus using the command: CREATE PRIVATE SYNONYM EDL_VU FOR mary. EMP DEPT_LOC_VU; then he can prefix the columns with this synonymn.
B. Scott can create a synonym for the EMP_DEPT_LOC_VU by using the command: CREATE SYNONYM EDL_VU FOR mary. EMP DEPT_LOC_VU; then he can prefix the columns with this synonym.
C. Scott can create a synonym for the EMP_DEPT_LOC_VU by using the command: CREATE LOCAL SYNONYM EDL_VU FOR mary. EMP DEPT_LOC_VU; then he can prefix the columns with this synonym.
D. Scott cannot create a synonym because synonyms can be created only for tables.
E. Scott cannot create any synonym for Mary's view. Mary should create a private synonym for the view and grant SELECT privilege on that synonym to Scott.

多项选择题Which two statements are true regarding the ORDER BY clause? （）

A.The sort is in ascending by order by default.
B.The sort is in descending order by default.
C.The ORDER BY clause must precede the WHERE clause.
D.The ORDER BY clause is executed on the client side.
E.The ORDER BY clause comes last in the SELECT statement.
F.The ORDER BY clause is executed first in the query execution.

多项选择题Which two tasks can your perform by using the TO_CHAR function? （）

A. Convert 10 to 'TEN'
B. Convert '10' to 10
C. Convert '10' to '10'
D. Convert 'TEN' to 10
E. Convert a date to a character expression
F. Convert a character expression to a date

多项选择题The CUSTOMERS table has these columns: CUSTOMER_ID NUMBER(4) NOT NULL CUSTOMER_NAME VARCHAR2(100) NOT NULL STREET_ADDRESS VARCHAR2(150) CITY_ADDRESS VARCHAR2(50) STATE_ADDRESS VARCHAR2(50) PROVINCE_ADDRESS VARCHAR2(50) COUNTRY_ADDRESS VARCHAR2(50) POSTAL_CODE VARCHAR2(12) CUSTOMER_PHONE VARCHAR2(20) The CUSTOMER_ID column is the primary key for the table. Which two statements find the number of customers? （）

A. SELECT TOTAL(*) FROM customer;
B. SELECT COUNT(*) FROM customer;
C. SELECT TOTAL(customer_id) FROM customer;
D. SELECT COUNT(customer_id) FROM customer;
E. SELECT COUNT(customers) FROM customer;
F. SELECT TOTAL(customer_name) FROM customer;

多项选择题Which four statements correctly describe functions that are available in SQL? （）

A. INSTR returns the numeric position of a named character.
B. NVL2 returns the first non-null expression in the expression list.
C. TRUNCATE rounds the column, expression, or value to n decimal places.
D. DECODE translates an expression after comparing it to each search value.
E. TRIM trims the heading of trailing characters (or both) from a character string.
F. NVL compares two expressions and returns null if they are equal, or the first expression of they are not equal.
G. NULLIF compares twp expressions and returns null if they are equal, or the first expression if they are not equal.