User SCOTT executes the following command on the EMP table but has not issued COMMIT, ROLLBACK, orany data definition language (DDL) command: SQL> SELECT ename FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno; SCOTT has opened another session to work with the database instance. Which three operations would waitwhen issued in SCOTT’s second session()
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The EMP table exists in your schema. You want to execute the following query: SELECT ename, sal FROM emp AS OF TIMESTAMP (SYSTIMESTAMP - INTERVAL '6' MINUTE) WHERE ename = 'ALLEN'; What are the minimum requirements for the statement to execute successfully? ()
试述Embden-Meyerhof-Paras(EMP)途径的特点EMP途径的特点。
The EMP table contains these columns: LAST_NAME VARCHAR2 (25) SALARY NUMBER (6,2) DEPARTMENT_ID NUMBER (6) You need to display the employees who have not been assigned to any department. You write the SELECT statement: SELECT LAST_NAME, SALARY, DEPARTMENT_ID FROM EMP WHERE DEPARTMENT_ID = NULL; What is true about this SQL statement ?()
User SCOTT executes the following command on the EMP table but has not issued COMMIT, ROLLBACK,or any data definition language (DDL) command: SQL> SELECT job FROM emp 2 WHERE job=’CLERK’ FOR UPDATE OF empno; SCOTT has opened another session to work with the database. Which three operations would wait when issued in SCOTT’s second session?()
The EMP table contains these columns: LAST NAME VARCHAR2(25) SALARY NUMBER(6,2) DEPARTMENT_ID NUMBER(6) You need to display the employees who have not been assigned to any department. You write the SELECT statement: SELECT LAST_NAME, SALARY, DEPARTMENT_ID FROM EMP WHERE DEPARMENT_ID = NULL; What is true about this SQL statement?()
You want to check the EMP table in the user, Scott’s schema for block corruption. You also want to fix the corrupted blocks, if any. How will you accomplish the required task?()
View the Exhibit and examine the structure of the EMP table. You executed the following command to add a primary key to the EMP table: ALTER TABLE emp ADD CONSTRAINT emp_id_pk PRIMARY KEY (emp_id) USING INDEX emp_id_idx; Which statement is true regarding the effect of the command?()
A user executes a query on the EMP table, which contains thousands of rows, to get details about employees in one of the departments. The user receives the following error: SQL> SELECT ename FROM emp WHERE deptno=10 ORDER BY sal; SELECT ename FROM emp WHERE deptno=10 ORDER BY sal * ERROR at line 1: ORA/x7f01157: cannot identify/lock data file 201 /x7f see DBWR trace file ORA/x7f01110: data file 201: ’/u01/app/oracle/oradata/orcl/temp01.dbf’ What is a possible reason?()