施工前的准备工作，是整个道路施工的重要环节，其主要工作内容，大致可归纳为（）。 进场准备。 组织准备。 技术准备。 物质准备。
You are working as a DBA at NetFx Corporation. You discover that the SCOTT schema is deleted by mistake. You decide to flash the database back to the time when the schema existed. Which view will you query to determine the estimated size of the flashback data that you require for your current target retention？（） V$FLASHBACK_DATABASE_LOG。 V$FLASHBACK_DATABASE_STAT。 V$DATABASE。 V$UNDOSTAT。
What is the result？（） Compilation fails.。 An exception is thrown at runtime.。 The code executes and prints "running".。 The code executes and prints "runningrunning".。 The code executes and prints "runningrunningrunning".。
Examine the structure of the EMPLOYEES, DEPARTMENTS, and TAX tables. For which situation would you use a nonequijoin query?（） To find the tax percentage for each of the employees.。 To list the name, job id, and manager name for all the employees.。 To find the name, salary, and department name of employees who are not working with Smith.。 To find the number of employees working for the Administrative department and earning less then 4000.。 To display name, salary, manager ID, and department name of all the employees, even if the employees do not have a department ID assigned.。
零件在径向位置上有偏重，其偏重总是停留在（）方向的最低位置。
实现五个目标应当坚持的指导思想是（）。
