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- 单项选择题 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?（） A、Create DDL INSERT triggers on the Employee. Task and Assignment entities.
B、Create CHECK constraints on the Task ID and Employee ID attributes in the Assignment entity.
C、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.
D、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.
- C
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