Technology Questions

The application layer of an R/3 System is made up of the application servers and the message server. Application programs in an R/3 System are run on application servers. The application servers communicate with the presentation components, the database, and also with each other, using the message server. All the data are stored in a centralized server. This server is called database server.

A foreign key is a reference to another table. It is used to establish relationships between tables. For example, relationship between employee and professor table. One employee can have multiple professors. The Primary key of employee becomes foreign key of professor.
Example:
create table employee ( id number NOT NULL, professor_id NOT NULL, Name varchar(200) Constraint prim_id Foreign key(id) references professor(professor_id) );

PL/SQL is Procedural Language SQL that is an extension of SQL that results in a more structural language composed of blocks. It is mainly used in writing applications that needs to be structured and has error handling.

The diamond problem is an ambiguity that can occur when a class multiply inherits from two classes that both descend from a common super class

.NET does not support multiple inheritance directly because in .NET, a class cannot inherit from more than one class. .NET supports multiple inheritance through interfaces.

SimpleTimeZone is a concrete subclass of TimeZone class. The TimeZone class represents a time zone, that is to be used with Gregorian calendar.

The SimpleTimeZone is created by using the base time zone offset from GMT time zone ID and rules, for starting and ending the time of daylight.

By default, primary key creates a clustered index on the column, whereas a unique key creates a non clustered index by default.

You should not use AJAX if:

             =>  You want the page to show in a search engine, such as Google, because WebCrawler does not execute JavaScript code.

             =>  The browser does not support JavaScript.

             =>  You want to create a secure application.