You are a database developer. You plan to design a database solution byusing SQL Server 2008. You are creating adataba seto support the office manager. Your database model has the following structure. The database design has the following business requirements: An employee can be assigned more than one task. Upon completion, thetask is deleted. When a task is deleted, the associated assignment is deleted. When an employee is nolonger available tocomple tea task, theemployee link to the assignment is replaced with a NULL value. You need to implement the business requirements to maintain data integrity. What should you do?（） ["Create DDL INSERT triggers on the Employee. Task and Assignment entities.","Create CHECK constraints on the Task ID and Employee ID attributes in the Assignment entity.","Create Foreign Keys constraints on the Task ID and EmployeeID attributes in the Assignment entity. Reference the Task and Employee entities respectively. Specify the appropriate On Delete action.","Create Foreign Keys constraints on the Task ID and Employee ID attributes in theTask and Employeeentities respectively. Reference the Assignment entity, and specify the appropriate On Delete action."]
参与示范
遗传毒性致癌物
设备的使用年限可与设备的（）相互转换。 ["运行量","使用强度","工作量","有形损耗"]
You have specified the warning and critical threshold values of an application tablespace to be 60% and 70%， respectively. From the tablespace space usage metrics， you find that the actual space usage has reached the specified warning threshold value， but no alerts have been generated. What could be the reason for this？（） ["The EVENT parameter was not set.","The SQL_TRACE parameter is set to FALSE","The Enterprise Manager Grid Control is not used.","The STATISTICS_LEVEL parameter is set to BASIC","The TIMED_STATISTICS parameter is set to FALSE"]
试述城市文化系统的运行过程。
