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?()
- A、Column definitions cannot be altered to add DEFAULT values.
- B、A change to the DEFAULT value affects only subsequent insertions to the table.
- C、Column definitions cannot be altered to add DEFAULT values for columns with a NUMBER data type.
- D、All the rows that have a NULL value for the SALARY column will be updated with the value 5000.
正确答案:B
答案解析:有
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