Declare @Id Int 
Select @Id = Id From sysobjects Where Name = 'tbl_HParvande'
if not Exists(SELECT * FROM syscolumns WHERE id = @Id  and Name = 'Active_Flag')
Begin
ALTER TABLE dbo.tbl_HParvande ADD Active_Flag bit NULL

ALTER TABLE dbo.tbl_HParvande ADD CONSTRAINT DF_tbl_HParvande_Active_Flag DEFAULT 1 FOR Active_Flag
End



Select @Id = Id From sysobjects Where Name = 'tbl_HParvande'
if not Exists(SELECT * FROM syscolumns WHERE id = @Id  and Name = 'Exp_Date')
Begin
  ALTER TABLE dbo.tbl_HParvande ADD Exp_Date smalldatetime
End