【云貝教育】Oracle 19c OCP 082題庫解析(1)
考試科目：1Z0-082
考試題量：90
通過分?jǐn)?shù)：60%
考試時(shí)間：150min
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本文為云貝教育郭一軍（微信：guoyJoe）原創(chuàng)，請(qǐng)尊重知識(shí)產(chǎn)權(quán)，轉(zhuǎn)發(fā)請(qǐng)注明出處，不接受任何抄襲、演繹和未經(jīng)注明出處的轉(zhuǎn)載。
1.Which two statements are true about space-saving features in an Oracle Database?
A.An index created with the UNUSABLE attribute has no segment.
B.Private Temporary Tables(PTTs)store metadata in memory only.
C.Private Temporary Tables(PTTs) when used, are always dropped at the next commit statement.
D.An index that is altered to be UNUSABLE will retain its segment.
E. A table that is truncated will always have all of its extents removed.
參考答案：AB
解析：
A:不可用索引會(huì)自動(dòng)刪除segment,但是索引分區(qū)后，某個(gè)分區(qū)的索引不可用，其它索引段還在的
B:私有臨時(shí)表這個(gè)特性18C才引入(https://docs.oracle.com/en/database/oracle/oracle-database/18/admin/managing-tables.html#GUID-9B373086-0760-4B18-9688-BACFF07EC74B)
C:私有臨時(shí)表和全局臨時(shí)表都有ON COMMIT DELETE ROWS和ON COMMIT PRESERVE ROWS的兩種分類(delete rows用于事務(wù)相關(guān),也就在事務(wù)結(jié)束后truncate data in the temporary table,preserve rows表示在會(huì)話結(jié)束后清除臨時(shí)表的數(shù)據(jù))
D:不可用的索引會(huì)被刪除段,已使用alter index unusable測(cè)試
E:普通表截?cái)嗪髸?huì)保留min_extents設(shè)置的初始區(qū)段大小
