Which two statements accurately describe a role?（） A role can be given to a maximum of 1000 users.。 A user can have access to a maximum of 10 roles.。 A role can have a maximum of 100 privileges contained in it.。 Privileges are given to a role by using the CREATE ROLE statement.。 A role is a named group of related privileges that can be granted to the user.。 A user can have access to several roles, and several users can be assigned the same role.。
发电机失磁后，机组转速（）。 升高。 降低。 不变。
Given： What is the result？（） Compilation fails.。 aAaA aAa AAaa AaA。 AAaa AaA aAa aAaA。 AaA AAaa aAaA aAa。 aAa AaA aAaA AAaa。
If a log file becomes corrupted， it may cause the database to stall. How would you correct such a situation？（） Recover the online redo log from backup.。 Delete and re-create the log file.。 Use the alter database clear logfile command to clear the log file.。 Shut down the database and restart it.。 Shut down the database and then mount it. Clear the log file with the alter database clear logfile command and then restart the database with alter database open resetlogs.。
瓶阀出厂时应（）出具合格证。 逐批；。 逐只；。 按比例；。 随机。
下列哪些对服务台应是可使用的（）
