Examine the structure of the EMPLOYEES table: EMPLOYEE_ID NUMBER NOT NULL, Primary Key EMP_NAME VARCHAR2(30) JOB_ID NUMBER/ SAL NUMBER MGR_ID NUMBER References EMPLOYEE_ID column DEPARTMENT_ID NUMBER Foreign key to DEPARTMENT_ID column of the DEPARTMENTS table You created a sequence called EMP_ID_SEQ in orderto populate sequential values for the EMPLOYEE_ID column of the EMPLOYEES table. Which two statements regarding the EMP_ID_SEQ sequence are true? ()
- A、You cannot use the EMP_ID_SEQ sequence to populate the JOB_ID column.
- B、The EMP_ID_SEQ sequence is invalidated when you modify the EMPLOYEE_ID column.
- C、The EMP_ID_SEQ sequence is not affected by modifications to the EMPLOYEES table.
- D、Any other column of NUMBER data type in your schema can use the EMP_ID_SEQ sequence.
- E、The EMP_ID_SEQ sequence is dropped automatically when you drop the EMPLOYEES table.
- F、The EMP_ID_SEQ sequence is dropped automatically when you drop the EMPLOYEE_ID column.
正确答案:C,D
答案解析:有
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