评估以下语句: ALTER TABLE employees ADD CONSTRAINT employee_id PRIMARY KEY; 该语句将返回以下哪种结果()
第1题:
PO_DETAILS表包含以下列: PO_NUM NUMBER NOT NULL, Primary Key PO_LINE_ID NUMBER NOT NULL, Primary Key PRODUCT_ID NUMBER Foreign Key to PRODUCT_ID column of the PRODUCTS table QUANTITY NUMBER UNIT_PRICE NUMBER(5,2) 请评估以下语句: ALTER TABLE po_details DISABLE CONSTRAINT po_details_pk CASCADE;此语句用于完成什么任务()
第2题:
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()
第3题:
DEPARTMENT 表包含以下列: DEPT_ID NUMBER, Primary Key DEPT_ABBR VARCHAR2(4) DEPT_NAME VARCHAR2(30) MGR_ID NUMBER EMPLOYEE 表包含以下列: EMPLOYEE_ID NUMBER EMP_LNAME VARCHAR2(25) EMP_FNAME VARCHAR2(25) DEPT_ID NUMBER JOB_ID NUMBER MGR_ID NUMBER SALARY NUMBER(9,2) HIRE_DATE DATE 请评估以下语句: ALTER TABLE employee ADD CONSTRAINT REFERENTIAL (mgr_id) TO department(mgr_id); 是以下哪个说法()
第4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()
第5题:
You own a table called EMPLOYEES with this table structure: EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE What happens when you execute this DELETE statement? DELETE employees;()
第6题:
Examine the structure of the EMPLOYEES and NEW_EMPLOYEES tables: EMPLOYEES EMPLOYEE_ID NUMBER Primary Key FIRST_NAME VARCHAR2(25) LAST_NAME VARCHAR2(25) HIRE_DATE DATE NEW_EMPLOYEES EMPLOYEE_ID NUMBER Primary Key NAME VARCHAR2 (60) Which DELETE statement is valid?()
第7题:
ALTER TABLE语句创建从EMPLOYEE表到DEPARTMENT表的引用约束条件
ALTER TABLE语句创建从DEPARTMENT表到EMPLOYEE表的引用约束条件
ADD CONSTRAINT子句存在语法错误,因此ALTER TABLE语句将会失败
ALTER TABLE语句执行成功,但不重新创建引用约束条件
第8题:
新创建一个对PO_NUM列的PRIMARYKEY约束条件
删除并重新创建对PO_NUM列的PRIMARYKEY以及FOREIGNKEY的约束条件
禁用依赖于PO_NUM列的所有FOREIGNKEY约束条件
禁用对PO_NUM列的约束条件,同时创建PRIMARYKEY索引
第9题:
You get an error because of a primary key violation.
The data and structure of the EMPLOYEES table are deleted.
The data in the EMPLOYEES table is deleted but not the structure.
You get an error because the statement is not syntactically correct.
第10题:
将返回语法错误
将向EMPLOYEES表添加约束条件
将改写EMPLOYEES表的一个现有约束条件
将启用EMPLOYEES表的一个现有约束条件
第11题:
更改employees表并禁用emp_manager_fk约束条件
向EMPLOYEES表添加FOREIGN KEY约束条件,要求经理必须已是雇员
向EMPLOYEES表添加FOREIGN KEY约束条件,要求经理标识应匹配每个雇员标识
更改employees表并添加FOREIGN KEY约束,要求每个雇员标识必须唯一
第12题:
INSERT INTO employees VALUES (NULL, 'JOHN','Smith');
INSERT INTO employees( first_name, last_name) VALUES ('JOHN','Smith');
INSERT INTO employees VALUES ('1000','JOHN','NULL');
INSERT INTO employees(first_name,last_name, employee_id) VALUES ('1000, 'john','Smith');
INSERT INTO employees (employee_id) VALUES (1000);
INSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, 'john',);
第13题:
您在公司的数据库中成功创建了名为SALARY的表。您现在要通过向引用EMPLOYEES表的匹配列的SALARY表添加FOREIGNKEY约束条件来建立EMPLOYEES表与SALARY表之间的父/子关系。尚未向SALARY表添加任何数据。应执行以下哪条语句()
第14题:
要向雇员表中的部门标识列添加FOREIGNKEY约束条件以引用部门表中的标识列,应该使用哪个语句()
第15题:
以下SQL命令执行什么操作() ALTER TABLE employees ADD CONSTRAINT emp_manager_fk FOREIGN KEY(manager_id) REFERENCES employees(employee_id).
第16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? ()
第17题:
The EMPLOYEES table is stored in the SAMPLE tablespace. The corresponding IPK_EMP index for the EMPLOYEES table’s primary key is stored in the INDX tablespace. Out of 12 partitions, only partition P1 of the SALES table is stored in the SAMPLE tablespace. Which object will be exported by this command?() exp system/manager tablespaces=SAMPLE
第18题:
You get an error because of a primary key violation.
The data and structure of the EMPLOYEES table are deleted.
The data in the EMPLOYEES table is deleted but not the structure.
You get an error because the statement is not syntactically correct.
第19题:
此语句会创建一个基于函数的索引
因为语法错误,此语句将失败
该语句将创建一个组合唯一索引
该语句将创建一个组合非唯一索引
第20题:
ALTER TABLE salary ADD CONSTRAINT fk_employee_id_01 FOREIGN KEY(employee_id)REFERENCES employees(employee_id)
ALTER TABLE salary ADD CONSTRAINT fk_employee_id_ FOREIGN KEY BETWEEN salary(employee_id)AND employees(employee_id)
ALTER TABLE salary FOREIGN KEY CONSTRAINT fk_employee_id_REFERENCES employees(employee_id)
ALTER TABLE salary ADD CONSTRAINT fk_employee_id_FOREIGN KEY salary(employee_id)=employees(employee_id)
第21题:
INSERT INTO employees VALUES ( NULL, 'John', 'Smith');
INSERT INTO employees( first_name, last_name) VALUES( 'John', 'Smith');
INSERT INTO employees VALUES ( '1000', 'John', NULL);
INSERT INTO employees (first_name, last_name, employee_id) VALUES ( 1000, 'John', 'Smith');
INSERT INTO employees (employee_id) VALUES (1000);
INSERT INTO employees (employee_id, first_name, last_name) VALUES ( 1000, 'John', ' ');
第22题:
Only the EMPLOYEES table.
Only the EMPLOYEES table and its corresponding primary key index.
The EMPLOYEES table and partition P1.
The EMPLOYEES table, IPK_EMP index, and the SALES table.
第23题:
ALTER INDEX ln_idx ON employees(first_name)
ALTER INDEX ln_idx TO employees(first_name)
ALTER INDEX ln_idx TO fn_idx ON employees(first_name)
以上都不能;您无法变更索引