Primary key and unique key are entity integrity constraints. The main difference between the two keys is that there can be multiple unique key columns with null values, whereas that there can only be one...

Class and Object are two most important concept of Object oriented programming language. The main difference between the two is that class is a blueprint which is used to create different objects of same type.

An ‘echo’ and a ‘print’ function is a language construct in PHP language. An ‘echo’ gives an output in one or more strings, while a ‘print’ gives an output only in one string.

In procedural programming the programs are executed with functions and the data of the programs can be easily accessed and changed, whereas in object oriented programming each program is made up of entities...

The Online Analytical Processing is designed to answer multi-dimensional queries, whereas the Online Transaction Processing is designed to facilitate and manage the usual business applications. While OLAP is...