Technology Questions

- Frames make it easier to navigate through a site. 

- The links that appear in the frame can appear through out the site.

strat_form using this we can open many layoutses
open_form using this we can open the layout
performance will be high

Oracle NOT NULL is used on a column to ensure that the value for that column can never be NULL.
Example:
Below, the constraint is that the id should never be NULL. If it is, oracle throws an error.
create table employee ( id number NOT NULL, Name varchar(200) );

It Return true if the argument is not a number.

A throw is used to throw an exception manually, where as throws is used in the case of checked exceptions, to tell the compiler that we haven't  handled the exception, so that the exception will be handled by the calling function.

Arrays can store data in a fix allotted space. The use of linked list allows more flexibility because space is dynamically allocated as needed.

An abstract class can have instance methods that implement a default behavior. An Interface can only declare constants and instance methods, but cannot implement default behavior and all methods are implicitly abstract. An interface has all public members and no implementation. An abstract class is a class which may have the usual flavors of class members (private, protected, etc.), but has some abstract methods.

=> When a consumer wants to buy a certain product, he go to the website and selects the product he wants to buy. 

=> Once the product is selected, the consumer transaction is moved to the online transaction server where he places an order. 

=> The informations is exchanged over a secure channel through a private gateway to a processing network. 

=> The networked banks accept or reject the transaction.

 All this happens in just a matter of seconds. E-commerce is a very secure due to the SSL (Secure Socket Layer) technology.