Create Table Emp
(
  Emp_ID    Number(10),
  Emp_Time  Number(1) Default 1,
  Emp_Code  VarChar2(10),
  Emp_Name  VarChar2(30),
  Del_Date  Date,
  Constraint PK_EMP Primary Key(Emp_ID),
  Constraint UQ_EMP_Time Unique(Emp_Time,Emp_Code)
)
/

Create Or Replace Trigger TRG_EMP_Befor Before Insert On Emp
For Each Row
Begin
  Select NVL(Max(Emp_ID),0) + 1 Into :New.Emp_ID From Emp;
End;
/

Create Or Replace Trigger TRG_EMP_After After Delete On Emp
For Each Row
Begin
   If(:Old.Emp_Time = 1)Then
      Insert Into Emp(EMP_TIME,EMP_CODE,EMP_NAME,DEL_DATE) 
  	  Values(2,:Old.Emp_CODE,:Old.Emp_NAME,SysDate);
   End If;
End;
/
