While Monitoring the space usage in your database that is in ARCHIVELOG mode you observed that the flash recovery area does not have enough free space to accommodate any more files and you do not have necessary permissions to add more space to it. Identify the two events that can occur in the event of a log switch? （）(Choose two.) An entry is created in the alert log file and the database instance continues to function normally。 The log switch hangs occur for transactions until free space is available in the flash recovery area。 The Oracle database server deletes a file that is on the obsolete file list to make free space in the flash recovery area。 The database instance status is implicitly changed to RESTRICTED mode and file creations to the flash recovery area are prevented。
引起旋转机械振动的主要原因有（）。 制造时，叶轮与转轴配合间隙不足。 转轴上出现横向疲劳裂纹。 轴承油膜涡动和油膜振荡。 旋转失速。
You want to create a tablespace to contain objects with block size 16 KB. But while configuring thestorage you find that the block size that you can provide is only 8 KB. Which configuration could have enabled the block selection of 16 KB（） choosing the extent allocation type to uniform。 choosing the Segment Space Management option to manual。 setting autoextension on for the data file mentioned for the tablespace。 setting the DB_16K_CACHE_SIZE parameter for the database instance to a nonzero value。
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_SEQEMP_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)。
简述如何有效利用幼儿园经费。
因火灾一个易熔塞溶化时，会发生哪种情况（）
