When you want to compare the same variable or expression with many different values, and execute a different piece of code depending on which value it equals to, the “if” statement might prove to be repetitive. This is where “switch” comes in.

What is XML-RPC?

RPC stands for Remote Procedure Call.

It is a set of specifications and implementations that makes applications running in different environments; different operating system can talk to each other by making remote procedure call. An RPC-based Web service is a collection of procedures that can be called by a remote client over the Internet. XML-RPC is the makes it easy for distributed systems and system interoperability. This allows a perl function to make a call to a Python method, or a Java Servlet to call a PHP function.

The date and time functions allow you to use the time of the server that PHP is running on so keep in mind that this function will depend on the local setting of your server. The basic PHP date and time functions let you format timestamps for use in database queries or simply for displaying the date and time in the browser window. PHP includes the following date and time functions:

A string is a series of characters. In PHP, a character is the same as a byte, that is, there are exactly 256 different characters possible. It is no problem for a string to become very large. There is no practical bound to the size of strings imposed by PHP, so there is no reason at all to worry about long strings. String values can be used literally or be assigned to variables.

Operators are used to perform operations or actions on variables. This can include assigning a value to a variable, performing addition with variables, comparing the value of variables, and to determine the status of a condition.

If you are looking for a data holder, which will be available anywhere in your script, including functions , then constants is the best option.

Array Variables

Arrays are special types that allow variables to store as many values as you want in the same variable. PHP supports numerically indexed arrays and associative arrays. An array in PHP is actually an ordered map. A map is a type that maps values to keys. Array variables consist of two parts - an index and an element. The array index, sometimes referred to as the array key, is a value used to identify or access array elements.

As in any Programming language, variables act as temporary place holders used to represent values used in a PHP script. There are  two main types of variables in PHP : scalar and array. Scalar variables are those which can store only a single value at a time , whare as  array variables are those which could have a list of values.  PHP scalar variables contain values of the following types:

The If Statement

It is often desirable when writing code to perform different actions based on different decision. In PHP this is possible using conditional statements - The if Statement, the if...else statement, and elseif statement.

The MySQL® database has become the world's most popular open source database because of its consistent fast performance, high reliability and ease of use. It's used in more than 6 million installations ranging from large corporations to specialized embedded applications on every continent in the world.

PHP provides support for MySQL through an array of functions that can be used to manipulate MySQL data. The purpose of this tutorial is to introduce those functions commonly used in PHP data-driven applications for retrieving, updating, inserting, and deleting data.

The common PHP MySQL functions are described below: