I have the below create table code:

```
CTranID int identity(1,1) constraint pk_CTrainID Primary Key,
CustomerID AS 'PB' + 
               cast(datepart(yy,getdate()) as varchar(25)) + 
               cast(datepart(mm,getdate()) as varchar(25)) + 
               RIGHT('000000000' + CAST(CTranID AS VARCHAR(10)), 9),

```

What is happening is that when the record inserts it goes as per current year and month.  

But as a testing I changed the system month and when I query in `T-SQL`, I see the previously inserted records as for the changed month.  

Where in case it should have been for the month before changing the system month.