How to Create an SQL Server 2008 INSERT Trigger for Efficient Employee Data Management?

SQL Server 2008 Insert Trigger for Employee Management

Managing employee data requires efficiently handling insertions into the EmployeeResult table while ensuring that the Employee table contains necessary employee information. This article addresses the creation of an INSERT trigger to address this need.

Understanding the Trigger Structure

The trigger will be defined on the EmployeeResult table and executed upon insertions. It aims to check for the existence of employee records in the Employee table and insert any missing employee information. The trigger requires the following inputs:

• Condition: A condition to evaluate whether an employee record exists in the Employee table.
• Insertion Values: The values to insert into the Employee table if the employee record does not exist.

Populating the Employee Table

Using the INSERTED logical table, we can retrieve the inserted data and filter it to identify employee and department pairs that do not currently exist in the Employee table. The following code demonstrates this process:

CREATE TRIGGER trig_Update_Employee
ON [EmployeeResult]
FOR INSERT
AS
BEGIN
    INSERT INTO [Employee] (Name, Department)
    SELECT DISTINCT i.Name, i.Department
    FROM INSERTED AS i
    LEFT JOIN Employee AS e
    ON i.Name = e.Name AND i.Department = e.Department
    WHERE e.Name IS NULL;
END

Conclusion

This trigger ensures that the Employee table contains all the necessary employee information when new data is inserted into the EmployeeResult table. It leverages the INSERTED logical table to efficiently insert missing employee records and maintain data integrity within the database.

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