2019OCP 12c 062题库更新大量新题-7

Posted 2021-10-21

7.daily_ords_lst is created in locally managed tablespace ORDERS_TBS which uses automatic segment space management.

CREATE TABLE daily_ords_list (ordno NUMBER, ord_date DATE) PCTFREE 20;

Which two are true ?

A) 80% of every data block in daily_ords_lst is reserved for row inserts.

B) pctfree eliminates row chaining during inserts.

C) pctfree can help reduce row migration during updates.

D) pctfree can help to minimize row chaining during inserts.

E) 20% of each data block in the table is reserved for row updates.

Answer：CE

(解析：pctfree 目的就是预防在 update 时造成行迁移，空出 20%就是为了给 update 使用，A 答案为什么是错的呢，因为块头也要占空间，所以真正使用的时候不会有 80%的可用空间。部落3：1015267481)