70-463 · Question #137
You administer a Microsoft SQL Server 2012 database. The database contains a table named Employee. Part of the Employee table is shown in the exhibit. (Click the Exhibit button.) Confidential informat
The correct answer is D. EmployeeNum. EmployeeNum (Employee Number) is the correct column for a unique constraint. EmployeeNum represents the business/natural key - a human-assigned identifier (such as a badge number or HR identifier) that uniquely identifies each employee and is used operationally to reference emplo
Question
You administer a Microsoft SQL Server 2012 database. The database contains a table named Employee. Part of the Employee table is shown in the exhibit. (Click the Exhibit button.) Confidential information about the employees is stored in a separate table named EmployeeData. One record exists within EmployeeData for each record in the Employee table. You need to assign the appropriate constraints and table properties to ensure data integrity and visibility. On which column in the Employee table should you a create a unique constraint?
Exhibits
Options
- ADateHired
- BDepartmentID
- CEmployeelD
- DEmployeeNum
- EFirstName
- FJobTitle
- GLastName
- HMiddleName
- IReportsToID
How the community answered
(47 responses)- D94% (44)
- G4% (2)
- H2% (1)
Explanation
EmployeeNum (Employee Number) is the correct column for a unique constraint. EmployeeNum represents the business/natural key - a human-assigned identifier (such as a badge number or HR identifier) that uniquely identifies each employee and is used operationally to reference employees across systems. While EmployeeID is likely the primary key (a surrogate key), the question asks for a unique constraint specifically, implying a secondary uniqueness requirement on the business identifier. EmployeeNum must be unique to reliably join with EmployeeData and to prevent duplicate employee records from different sources. Other columns like FirstName, LastName, DepartmentID, JobTitle, and ReportsToID are not unique per employee and cannot serve as unique identifiers.
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