DataSource Controls :: SQL Server 2005 Constraint?

let say i have 2 table (PARENT and STUDENT table)

the structure for both table are

STUDENT
PARENT
student_id (PK) parent_id (PK)
student_parent (FK) parent_status (the value is either ACTIVE OR INACTIVE)

- parent_id is refer by STUDENT table as a foreign key

- now i want to inactive the status for parent

- i want my system pop out a message something like "The parent you want to inactive is refer by a student, inactive is not allow"

- is it any constraint in SQL Server 2005 to help me check whether parent it is refer by student table? The concept i want to use is something like delete constraint in SQL Server 2005 mean it is not allow to delete a person who is refer by a student in STUDENT table.