> And if I give a example to support the following note,
> there is package SOLOMON. It's Microsoft product. This
> software stores the data in two databses of SQL Server 7.0
> or 2000 (1) SYSTEM DATABASE (2) APPLICATION DATABASE.
> There are about 1500 tables in these two databases. No
> table level constaints, no coulmn level constraints, no
> triggers, etc. have been defined at database level. The
> ingerity of database is matained by the front-end
> application (Solomon Kernel) written in Visual Basic.
> When we develop a package using front end like Visual
> Basic etc. then we can write code to validate what kind of
> data the user can enter, save, update or delete. For
> example, if we want the Name should not be greater than 20
> characters, we can write code for this validation. If we
> want that EmpID should be unique, we can write code for
> this. If we want that Salary should always be a positive
> number. I mean we can write code to completely manage how
> the data should be delete/saved/updated in our database.
> Now my questions is then why do we have to the double
> work. Then where is the need to define the constraints
> (column level or table level) in the database tables if
> everything we can do in the Front-end development
> language. Also, even we if we define the constraints in
> the database tables still to check whether there is any
> violation of those constraints we have do write code in
> front-end application at least to trap the error to know
> constraint failed?