I have implemented the object using a unique key as usual.

But in addition to the auto-increment number, there should be a human
readable alpha-numeric number for objects like customer code or order
code.

e.g.:
CUS22456
ORD_A4567

Logic for implementing these codes can be encapsulated inside the
respective classes. In successful transaction the current number
should be saved with the object and it should update in the database
as the last number for the next object (customer or order).
What is the best way it implement this using NHibernate ? Is there any
special way to do his using the mapping file? Or is there any way to
trap the successful transaction of the current object. So this can be
easily handled with the code.

Koolb

It seems like a better idea to have the "user readable" number being calculated from the Id of the object. That way you wont have 2 series of numbers to keep track off in the database.

You wont have a record of the number in the database then though, if that is important, it should only matter if you want to change the method for calculating the human readable number..

As Dan said, what you can do is adding "CUS" or "ORD" to the ID before displaying it... (you can prefix a number of 0 if you want)

eg:
ORD00107

Let

You can try programming your own ID generator, or using an interceptor to provide the ID value before saving the object.

I saw some samples about how to impliment a custom ID generator using hibernate/Java. But couldn't find any .NET samples. But can I impliment a custom number generator for a property ?

Do you mind explaining how to impliment a interceptor.

I implemented the code by using a getter and returning concatenated string of Prefix + ID. But I would really like to know whether I can do it using custom ID generator for a property? I would also like to know what you meant my interceptor.