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?（）
CREATE INDEX NAME _IDX (first_name, last_name);
CREATE INDEX NAME _IDX (first_name, AND last_name)
CREATE INDEX NAME_IDX ON (First_name, last_name);
CREATE INDEX NAME_IDX ON employees (First_name, AND last_name);
CREATE INDEX NAME_IDX ON employees (First_name, last_name);
CREATE INDEX NAME_IDX FOR employees (First_name, last_name);
单选题
User Mary has a view called EMP_DEPT_LOC_VU that was created based on the EMPLOYEES, DEPARTMENTS, and LOCATIONS tables. She has the privilege to create a public synonym, and would like to create a synonym for this view that can be used by all users of the database.Which SQL statement can Mary use to accomplish that task?（）
CREATE PUBLIC SYNONYM EDL_VU ON emp_dept_loc_vu
CREATE PUBLIC SYNONYM EDL:VU FOR mary (emp_dept_loc_vu);
CREATE PUBLIC SYNONYM EDL_VU FOR emp _dept_loc_vu;
CREATE SYNONYM EDL_VU ON emp_dept_loc_vu FOR EACH USER;
CREATE SYNONYM EDL_VU FOR EACH USER ON emp_dept_loc_vu
CREATE PUBLIC SYNONYM EDL_VU ON emp_dept_loc_vu FOR ALL USERS;
多选题
Which three statements about subqueries are true? （）
A main query can have more than one subquery.
A subquery can have more than one main query.
The subquery and main query must retrieve data from the same table.
The subquery and main query can retrieve data from different tables.
Only one column or expression can be compared between the subquery and main query.
Multiple columns or expression can be compared between the subquery and main query.
多选题
Which two statements are true about constraints? （）
The UNIQUE constraint does not permit a null value for the column.
A UNIQUE index gets created for columns with PRIMARY KEY and UNIQUE constraints.
The PRIMARY KEY and FOREIGN KEY constraints create a UNIQUE index.
The NOT NULL constraint ensures that null values are not permitted for the column.
单选题
What is necessary for your query on an existing view to execute successfully?（）
The underlying tables must have data.
You need SELECT privileges on the view.
The underlying tables must be in the same schema.
You need SELECT privileges only on the underlying tables.
单选题
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL EMP_NAME VARCHAR2(30) JOB_ID VARCHAR2(20) SAL NUMBER MGR_ID NUMBER DEPARTMENT_ID NUMBER You want to create a SQL script file that contains an INSERT statement. When the script is run, the INSERT statement should insert a row with the specified values into the EMPLOYEES table. The INSERT statement should pass values to the table columns as specified below: EMPLOYEE_ID: Next value from the sequence EMP_ID_SEQ EMP_NAME and JOB_ID: As specified by the user during run time, through substitution variables SAL: 2000 MGR_ID: No value DEPARTMENT_ID: Supplied by the user during run time through substitution variable. The INSERT statement should fail if the user supplies a value other than 20 or 50. Which INSERT statement meets the above requirements?（）
INSERT INTO employees VALUES (emp_id_seq.NEXTVAL, '&ename', '&jobid', 2000, NULL, &did);
INSERT INTO employees VALUES (emp_id_seq.NEXTVAL, '&ename', '&jobid', 2000, NULL, &did IN (20,50));
INSERT INTO (SELECT * FROM employees WHERE department_id IN (20,50)) VALUES (emp_id_seq.NEXTVAL, '&ename', '&jobid', 2000, NULL, &did);
INSERT INTO (SELECT * FROM employees WHERE department_id IN (20,50) WITH CHECK OPTION) VALUES (emp_id_seq.NEXTVAL, '&ename', '&jobid', 2000, NULL, &did);
INSERT INTO (SELECT * FROM employees WHERE (department_id = 20 AND department_id = 50) WITH CHECK OPTION ) VALUES (emp_id_seq.NEXTVAL, '&ename', '&jobid', 2000, NULL, &did);
单选题
You need to modify the STUDENTS table to add a primary key on the STUDENT_ID column. The table is currently empty. Which statement accomplishes this task?（）
ALTER TABLE students ADD PRIMARY KEY student_id;
ALTER TABLE students ADD CONSTRAINT PRIMARY KEY (student_id);
ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY student_id;
ALTER TABLE students ADD CONSTRAINT stud_id_pk PRIMARY KEY (student_id);
ALTER TABLE students MODIFY CONSTRAINT stud_id_pk PRIMARY KEY (student_id);
单选题
Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL EMP_NAME VARCHAR2(30) JOB_ID VARCHAR2(20) DEFAULT 'SA_REP' SAL NUMBER COMM_PCT NUMBER MGR_ID NUMBER DEPARTMENT_ID NUMBER You need to update the records of employees 103 and 115. The UPDATE statement you specify should update the rows with the values specified below: JOB_ID: Default value specified for this column definition. SAL: Maximum salary earned for the job ID SA_REP. COMM_PCT: Default value specified for this commission percentage column, if any. If no default value is specified for the column, the value should be NULL. DEPARTMENT_ID: Supplied by the user during run time through substitution variable. Which UPDATE statement meets the requirements?（）
UPDATE employees SET job_id = DEFAULT AND Sal = (SELECT MAX(sal) FROM employees WHERE job_id = 'SA_REP') AND comm_pct = DEFAULT AND department_id = &did WHERE employee _id IN (103,115);
UPDATE employees SET job_id = DEFAULT AND Sal = MAX(sal) AND comm_pct = DEFAULT OR NULL AND department_id = &did WHERE employee_id IN (103,115) AND job _ id = 'SA_ REP';
UPDATE employees SET job_id = DEFAULT, Sal = (SELECT MAX(sal) FROM employees WHERE job_id = 'SA_REP'), comm_pct = DEFAULT, department_id = &did WHERE employee_id IN (103,115);
UPDATE employees SET job_id = DEFAULT, Sal = MAX(sal), comm_pct = DEFAULT, department_id = &did WHERE employee_id IN (103,115) AND job _ id = 'SA_ REP';
UPDATE employees SET job_id = DEFAULT, Sal = (SELECT MAX(sal) FROM employees WHERE job_id = 'SA_REP') comm_pct = DEFAULT OR NULL, department_id = &did WHERE employee_id IN (103,115);
单选题
The EMPLOYEES table has these columns:LAST_NAME VARCHAR2(35) SALARY NUMBER(8,2) HIRE_DATE DATEManagement wants to add a default value to the SALARY column. You plan to alter the table by using this SQL statement:ALTER TABLE EMPLOYEES MODIFY (SALARY DEFAULT 5000);Which is true about your ALTER statement?（）
Column definitions cannot be altered to add DEFAULT values.
A change to the DEFAULT value affects only subsequent insertions to the table.
Column definitions cannot be altered to add DEFAULT values for columns with a NUMBER data type.
All the rows that have a NULL value for the SALARY column will be updated with the value 5000.
单选题
Which SQL statement defines the FOREIGN KEY constraint on the DEPTNO column of the EMP table?（）
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));
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