在室外变电站二次接线和照明回路上的工作,不需高压设备停电,只需做一点安全措施,应填用第二种工作票
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In your test database, you have created the ORDERS table as an index-organized table (IOT). To facilitate faster querying, you have created a mapping table and a bitmap index on the ORDER_FILLED column. You observe that the query performance degrees when users perform a large volume of transactions. While investigating the reason, you find that the mapping table segment is fragmented, leading to poor performance. Which option would you use to defragment the mapping table without affecting the original table data?()
A. Export and import the mapping table.
B. Drop and re-create the mapping table.
C. Truncate the mapping table and reinsert the values.
D. Use the ALTER TABL. REBUILD command to defragment the mapping table.
PCR反应过程中需使用()。
A. 限制性核酸内切酶
B. DNA连接酶
C. DNA聚合酶
DNA修饰酶