Necesitarás,
- Elimine la restricción de clave externa existente,
- Agregue uno nuevo con
ON DELETE CASCADE
configuración habilitada.
Algo como:
ALTER TABLE dbo.T2
DROP CONSTRAINT FK_T1_T2 -- or whatever it's called
ALTER TABLE dbo.T2
ADD CONSTRAINT FK_T1_T2_Cascade
FOREIGN KEY (EmployeeID) REFERENCES dbo.T1(EmployeeID) ON DELETE CASCADE