A customer requires a Web service which ensures message deli

正确答案：A
解析：Explanation: Adding an appropriate UPDATE trigger that notifies the service manager whenever a complaint is marked is closed would accomplish the requirements. The client applications application would not have to be changed.

Note: In SQL Server 2000, triggers are a special type of stored procedure that fire automatically when an UPDATE, INSERT, or DELETE statement is issued against a table or view. Triggers are powerful tools that can be used to enforce business rules automatically when data is modified and can automate the processing for a company. Like stored procedures, triggers contain Transact-SQL statements which can include instructions to send an e-mail message when a particular column is updated

Incorrect Answers:
B: If a stored procedure is created and used the client application would have to be adjusted
accordingly. But we don’t want to make any changes in the client application.

Note: A stored procedure is a set of Transact-SQL statements compiled into a single execution plan and can return data as output parameters, which can return either data or a cursor variable; return codes, which are always an integer value; a result set for each SELECT statement contained in the stored procedure or any other stored procedures called by the stored procedure; or as a global cursor that can be referenced outside the stored procedure.

Stored procedures assist in achieving a consistent implementation of logic across applications as the SQL statements and logic needed to perform. a task can be coded and tested once in a stored procedure. Thereafter each application or user that needs to perform. that task can execute the stored procedure.

Coding business logic into a single stored procedure also offers a single point of control for ensuring that business rules are correctly enforced. Stored procedures can also be used to customize security permissions in much the same way as views. Stored procedure permissions can be used to prevent users from modifying data in certain columns and then grant users permissions to execute the procedure.

C: If a user defined function is created and used the client application would have to be adjusted accordingly. But we don’t want to make any changes in the client application.

Note: In programming languages, functions are subroutines used to encapsulate frequently performed logic. Any code that must perform. the logic incorporated in a function can call the function rather than having to repeat all of the function logic. SQL Server 2000 supports built-in functions and user-defined functions.

Built-in functions operate as defined in the Transact-SQL Reference and cannot be modified while user-defined functions allow the user to define their own Transact-SQL functions using the CREATE FUNCTION statement. User-defined functions take zero or more input parameters, and return a single value. Some user-defined functions return a single, scalar data value, such as an int, char, or decimal value.

D: Just creating a rule would only check the input, it would not notify the service manager as required.

Note: Rules are a backward-compatibility feature of SQL Server 2000 and performs the same functions as CHECK constraints. CHECK constraints are the preferred, standard way to restrict the values in a column as they are more concise than rules.

参考答案：D

参考答案：A