Technology Questions

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

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 purpose of garbage collection is to identify and discard objects that are no longer needed by a program so that their resources can be reclaimed and reused. A Java object is subject to garbage collection when it becomes unreachable to the program in which it is used.

SQL is a structured query language while PL/SQL is an extension of SQL by introducing a procedural flow. PL/SQL has blocks of statements. PL/SQL works like other procedural languages and has concepts like control statements, sequential statements, exception handling etc.

The flow chart gives a clear graphical representation of an implemented process. This makes the system simple to understand for all persons involved in the project. 

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.

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.

As far PHP concern it only support single Inheritance in scripting. we can also use interface to achieve multiple inheritance.