“雇员”表在LAST_NAME列上有一个名为LN_IDX的索引。您要将此索引更改为FIRST_NAME列的索引。以下哪条SQL语句将实现此操作（）A、ALTER INDEX ln_idx ON employees（first_name）B、ALTER INDEX ln_idx TO employees（first_name）C、ALTER INDEX ln_idx TO fn_idx ON employees（first_name）D、以上都不能；您无法变更索引
“雇员”表在LAST_NAME列上有一个名为LN_IDX的索引。您要将此索引更改为FIRST_NAME列的索引。以下哪条SQL语句将实现此操作（）
- A、ALTER INDEX ln_idx ON employees（first_name）
- B、ALTER INDEX ln_idx TO employees（first_name）
- C、ALTER INDEX ln_idx TO fn_idx ON employees（first_name）
- D、以上都不能；您无法变更索引
相关考题：
Examine the structure of the EMPLOYEES table:Column name Data type RemarksEMPLOYEE_ID NUMBER NOT NULL, Primary KeyLAST_NAME VARCNAR2(30)FIRST_NAME VARCNAR2(30)JOB_ID NUMBERSAL NUMBERMGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBERYou need to create an index called NAME_IDX on the first name and last name fields of the EMPLOYEES table. Which SQL statement would you use to perform this task? （）A. CREATE INDEX NAME _IDX (first_name, last_name);B. CREATE INDEX NAME _IDX (first_name, AND last_name)C. CREATE INDEX NAME_IDX ON (First_name, last_name);D. CREATE INDEX NAME_IDX ON employees (First_name, AND last_name);E. CREATE INDEX NAME_IDX ON employees (First_name, last_name);F. CREATE INDEX NAME_IDX FOR employees (First_name, last_name);
在SQL Server 2000中，现要在employees表的first_name和last_name列上建立一个唯一的非聚集复合索引，其中first_name列数据的重复率是5%，last_name列数据的重复率是10%。请补全下列语句使以first_name和last_name列作为条件的查询效率最高。CREATE UNIQUE NONCLUSTERED INDEX Idx_NameON employees(______)
如果希望更新表authors中的first_name列为非空，那么可以使用哪个语句？（）A、alter table authors add first_name not nullB、alter table authors modify first_name not nullC、alter table authors alter first_name not nullD、alter table authors drop first_name not null
“雇员”表有一个基于“姓氏”列的名为“姓氏IDX”的索引。您需要更改此索引，使其基于“名字”列。哪条SQL语句将完成此任务？（）A、ALTERINDEX姓氏_idxON雇员（名字）B、ALTERINDEX姓氏_idxTO雇员（名字）C、ALTERINDEX姓氏_idxTO名字索引ON雇员（名字）D、上述各项度不是。不能对索引执行ALTER操作
您要对EMPLOYEES表的FIRST_NAME和LAST_NAME列创建一个组合索引。以下哪条语句将完成此任务（）A、CREATE INDEXfl_idx ON employees（first_name last_name）B、CREATE INDEXfl_idx ON employees（first_name），employees（last_name）C、CREATE INDEXfl_idx ON employees（first_name，last_name）D、CREATE INDEXfl_idx ON employees（first_name）；CREATE INDEXfl_idx ON employees（last_name）
“雇员”表包含以下列： EMPLOYEE_ID NOT NULL, Primary Key SSNUM NOT NULL, Unique LAST_NAME VARCHAR2(25) FIRST_NAME VARCHAR2(25) DEPARTMENT_ID NUMBER 部门表中 DEPARTMENT_ID 列的外键 SALARY NUMBER(8,2) 如果执行以下语句： CREATE INDEX emp_name_idx ON employees(last_name, first_name); 以下哪个说法是的（）A、此语句会创建一个基于函数的索引B、因为语法错误，此语句将失败C、该语句将创建一个组合唯一索引D、该语句将创建一个组合非唯一索引
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE Which INSERT statement is valid?（）A、INSERT INTO employees (employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01/01/01);B、INSERT INTO employees(employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01 january 01');C、INSERT INTO employees(employee_id, first_name, last_name, Hire_date) VALUES (1000, 'John', 'smith', To_ date ('01/01/01));D、INSERT INTO employees(employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01-Jan-01');
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) Which three statements inserts a row into the table? （）A、INSERT INTO employees VALUES (NULL, 'JOHN','Smith');B、INSERT INTO employees( first_name, last_name) VALUES ('JOHN','Smith');C、INSERT INTO employees VALUES ('1000','JOHN','NULL');D、INSERT INTO employees(first_name,last_name, employee_id) VALUES ('1000, 'john','Smith');E、INSERT INTO employees (employee_id) VALUES (1000);F、INSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, 'john',");
Which three statements inserts a row into the table?（）A、INSERT INTO employees VALUES ( NULL, ‘John’,‘Smith’);B、INSERT INTO employees( first_name, last_name) VALUES(‘John’,‘Smith’);C、INSERT INTO employees VALUES (‘1000’,‘John’,NULL);D、INSERT INTO employees(first_name,last_name, employee_id) VALUES ( 1000, ‘John’,‘Smith’);E、INSERT INTO employees (employee_id) VALUES (1000);F、INSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, ‘John’,‘’);
Examine the structure of the EMPLOYEES table: Column name Data type Remarks EMPLOYEE_ID NUMBER NOT NULL, Primary Key LAST_NAME VARCNAR2(30) FIRST_NAME VARCNAR2(30) JOB_ID NUMBER SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER You need to create an index called NAME_IDX on the first name and last name fields of the EMPLOYEES table. Which SQL statement would you use to perform this task? （）A、CREATE INDEX NAME _IDX (first_name, last_name);B、CREATE INDEX NAME _IDX (first_name, AND last_name)C、CREATE INDEX NAME_IDX ON (First_name, last_name);D、CREATE INDEX NAME_IDX ON employees (First_name, AND last_name);E、CREATE INDEX NAME_IDX ON employees (First_name, last_name);F、CREATE INDEX NAME_IDX FOR employees (First_name, last_name);
The EMPLOYEES table has six indexes and DML operations are slow. Which command begins monitoring the EMPLOYEE_IDX_FK index to determine whether it has been used by an execution plan？（）A、ALTER TABLE employees monitor index employee_idx_fk; B、ALTER INDEX employee_idx_fk monitoring on; C、ALTER TABLE employees monitor all indexes; D、ALTER INDEX employee_idx_fk monitoring usage;
当需要重建某个索引ix_customername，可以使用（）方式。A、ALTER INDEX ix_customername REBUILDB、ALTER INDEX ix_customername BUILDC、UPDATE INDEX ix_customername BUILDD、UPDATE INDEX ix_customername REBUILD
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE Which UPDATE statement is valid?（）A、UPDATE employees SET first_name = 'John' SET last_name ='Smith' WHERE employee_id = 180;B、UPDATE employees SET first_name = 'John', SET last_name ='Smith' WHERE employee_id = 180;C、UPDATE employees SET first_name = 'John' AND last_name ='Smith' WHERE employee_id = 180;D、UPDATE employees SET first_name = 'John', last_name ='Smith' WHERE employee_id = 180;
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2 (25) LAST_NAME VARCHAR2 (25) HIRE_DATE DATE Which UPDATE statement is valid? （）A、UPDATE employees SET first_name = 'John' SET last_name = 'Smith' WHERE employee_id = 180;B、UPDATE employees SET first_name = 'John', SET last_name = 'Smoth' WHERE employee_id = 180;C、UPDATE employee SET first_name = 'John' AND last_name = 'Smith' WHERE employee_id = 180;D、UPDATE employee SET first_name = 'John', last_name = 'Smith' WHERE employee_id = 180;
单选题“雇员”表包含以下列： EMPLOYEE_ID NOT NULL, Primary Key SSNUM NOT NULL, Unique LAST_NAME VARCHAR2(25) FIRST_NAME VARCHAR2(25) DEPARTMENT_ID NUMBER 部门表中 DEPARTMENT_ID 列的外键 SALARY NUMBER(8,2) 如果执行以下语句： CREATE INDEX emp_name_idx ON employees(last_name, first_name); 以下哪个说法是的（）A此语句会创建一个基于函数的索引B因为语法错误，此语句将失败C该语句将创建一个组合唯一索引D该语句将创建一个组合非唯一索引
多选题Which three statements inserts a row into the table?（）AINSERT INTO employees VALUES ( NULL, ‘John’,‘Smith’);BINSERT INTO employees( first_name, last_name) VALUES(‘John’,‘Smith’);CINSERT INTO employees VALUES (‘1000’,‘John’,NULL);DINSERT INTO employees(first_name,last_name, employee_id) VALUES ( 1000, ‘John’,‘Smith’);EINSERT INTO employees (employee_id) VALUES (1000);FINSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, ‘John’,‘’);
多选题Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) Which three statements insert a row into the table? （）AINSERT INTO employees VALUES ( NULL, 'John', 'Smith');BINSERT INTO employees( first_name, last_name) VALUES( 'John', 'Smith');CINSERT INTO employees VALUES ( '1000', 'John', NULL);DINSERT INTO employees (first_name, last_name, employee_id) VALUES ( 1000, 'John', 'Smith');EINSERT INTO employees (employee_id) VALUES (1000);FINSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, 'John', ' ');
单选题Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2 (25) LAST_NAME VARCHAR2 (25) HIRE_DATE DATE Which UPDATE statement is valid? （）AUPDATE employees SET first_name = 'John' SET last_name = 'Smith' WHERE employee_id = 180;BUPDATE employees SET first_name = 'John', SET last_name = 'Smoth' WHERE employee_id = 180;CUPDATE employee SET first_name = 'John' AND last_name = 'Smith' WHERE employee_id = 180;DUPDATE employee SET first_name = 'John', last_name = 'Smith' WHERE employee_id = 180;
单选题如果希望更新表authors中的first_name列为非空，那么可以使用哪个语句？（）Aalter table authors add first_name not nullBalter table authors modify first_name not nullCalter table authors alter first_name not nullDalter table authors drop first_name not null
单选题Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2 (25) LAST_NAME VARCHAR2 (25) HIRE_DATE DATE Which UPDATE statement is valid?（）AUPDATE employees SET first_name = 'John' SET last_name = 'Smith' WHERE employee_id = 180;BUPDATE employees SET first_name = 'John', SET last_name = 'Smoth' WHERE employee_id = 180;CUPDATE employee SET first_name = 'John' AND last_name = 'Smith' WHERE employee_id = 180;DUPDATE employee SET first_name = 'John', last_name = 'Smith' WHERE employee_id = 180;
单选题“雇员”表在LAST_NAME列上有一个名为LN_IDX的索引。您要将此索引更改为FIRST_NAME列的索引。以下哪条SQL语句将实现此操作（）AALTER INDEX ln_idx ON employees（first_name）BALTER INDEX ln_idx TO employees（first_name）CALTER INDEX ln_idx TO fn_idx ON employees（first_name）D以上都不能；您无法变更索引
单选题Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE Which UPDATE statement is valid?（）AUPDATE employees SET first_name = 'John' SET last_name ='Smith' WHERE employee_id = 180;BUPDATE employees SET first_name = 'John', SET last_name ='Smith' WHERE employee_id = 180;CUPDATE employees SET first_name = 'John' AND last_name ='Smith' WHERE employee_id = 180;DUPDATE employees SET first_name = 'John', last_name ='Smith' WHERE employee_id = 180;
单选题Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE Which INSERT statement is valid?（）AINSERT INTO employees (employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01/01/01);BINSERT INTO employees(employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01 january 01');CINSERT INTO employees(employee_id, first_name, last_name, Hire_date) VALUES (1000, 'John', 'smith', To_ date ('01/01/01));DINSERT INTO employees(employee_id, first_name, last_name, hire_date) VALUES (1000, 'John', 'smith','01-Jan-01');
多选题Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) Which three statements inserts a row into the table? （）AINSERT INTO employees VALUES (NULL, 'JOHN','Smith');BINSERT INTO employees( first_name, last_name) VALUES ('JOHN','Smith');CINSERT INTO employees VALUES ('1000','JOHN','NULL');DINSERT INTO employees(first_name,last_name, employee_id) VALUES ('1000, 'john','Smith');EINSERT INTO employees (employee_id) VALUES (1000);FINSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, 'john',);
单选题Examine the structure of the EMPLOYEES table: Column name Data type Remarks EMPLOYEE_ID NUMBER NOT NULL, Primary Key LAST_NAME VARCNAR2(30) FIRST_NAME VARCNAR2(30) JOB_ID NUMBER SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER You need to create an index called NAME_IDX on the first name and last name fields of the EMPLOYEES table. Which SQL statement would you use to perform this task? （）ACREATE INDEX NAME _IDX (first_name, last_name);BCREATE INDEX NAME _IDX (first_name, AND last_name)CCREATE INDEX NAME_IDX ON (First_name, last_name);DCREATE INDEX NAME_IDX ON employees (First_name, AND last_name);ECREATE INDEX NAME_IDX ON employees (First_name, last_name);FCREATE INDEX NAME_IDX FOR employees (First_name, last_name);