Unit 8.2. Advanced Uses of SQL’S NVL and DECODE Functions

Dynamic Web applications often require users to input values in a form, such as when users perform data entry or request a search based on their input. If you do not restrict the kind of input entered into your Web interface, then it is possible for many different values to be passed to your underlying Oracle PL/SQL procedure. Moreover, it is possible that your user may choose to not enter any value(s) at all before submitting the form, and NULL values could be passed to the application procedure. If DEFAULT values are not defined for your input parameters, then it is necessary for you to be able to handle NULL values in your server-side code.

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