齿轮泵噪音较大且压力较低，一般用于（）系统中。
下列科学家，对于第二次工业革命直接产生重大影响的是（）。 拉瓦锡。 法拉第。 达尔文。 道尔顿。
You upgraded from a previous Oracle database version to Oracle Database version to Oracle Database12c. Your database supports a mixed workload. During the day, lots of insert, update, and deleteoperations are performed. At night, Extract, Transform, Load (ETL) and batch reporting jobs are run. The ETL jobs perform certain database operations using two or more concurrent sessions.After the upgrade, you notice that the performance of ETL jobs has degraded. To ascertain the cause ofperformance degradation, you want to collect basic statistics such as the level of parallelism, totaldatabase time, and the number of I/O requests for the ETL jobs. How do you accomplish this?（） Examine the Active Session History (ASH) reports for the time period of the ETL or batch reporting runs.。 Enable SQL tracing for the queries in the ETL and batch reporting queries and gather diagnostic data from the trace file.。 Enable real-time SQL monitoring for ETL jobs and gather diagnostic data from the V$SQL_MONITOR view.。 Enable real-time database operation monitoring using the DBMS_SQL_MONITOR.BEGIN_OPERATION function, and then use the DBMS_SQL_MONITOR.REPORT_SQL_MONITOR function to view the required information.。
变压站（所）内铝金属性的设备接头过热后其颜色会变为（）。 红色。 黑色。 灰白色。
如果要求每当光标进入edit编辑框中时，编辑框都清空，可以在哪个事件处理程序中编写代码实现（） OnClick。 OnMouseMove。 OnKeyPress。 OnEnter。
Identify four uses of the Oracle Scheduler.（）
