Are you interested to find out more about the Simple PHP guide, and whether or not it is worth getting? With so many tutorials available on the internet, it can be very confusing trying to put all the information together to study systematically. This article will discuss how this scripting language works in general, and what is contained in the Simple PHP guide.

1. What Exactly Is PHP?

It is a server side scripting language that can be easily combined with HTML tags. It has been reconstructed into a web language today.

2. How Does It Work?

It works like standard programming language whereby it maintains the if/else condition statements, loops and subroutines. It is easily identified by the curly brackets { } used to define the start and end of statements. Users will need to use a

Finally, when you are done scripting a page in PHP, remember to save the file with the extension .php, and remember that .php files can still contain HTML tags within them.

3. Why Should You Learn PHP?

It is the most popular knowledge to have when you want your web pages to handle form data submitted by users. It also allows customization and building of dynamic pages. Best of all, it can connect to any SQL database, allowing you or your users to store, edit and delete any information from your web pages.

4. Review of Simple PHP Guide

This guide is compiled by Robert Plank and it is essentially like a step by step course for learning this scripting language. With the abundance of information available on the internet, it is very confusing to know where to start and end.

5. What Is Contained In This Package?

It lays out all the essential PHP skills in 17 chapters, complete with quizzes at the end of every chapter to test your understanding. 22 useful code snippets are included so you can stick them into your web page and be used immediately. Simple PHP guide is highly recommended if you want a full grasp of this scripting language quickly.

Don't be fooled by seeming simplicity. A lot of developers get comfortable with a certain way of designing a database for their web applications that they miss out on techniques they should rather employ to make things run faster and more efficiently. A lot of developers don't bear in mnd that the small site they are creating now might grow into something incredibly large and complex, and the database they designed has become bloated and doesn't scale well to meet the demands of the increased traffic.

This article hopes to provide web developers with a few techniques to help make their database and queries faster and more efficient.

1. Avoid Character Types

When you are designing a database, it is so easy to set all data types to the VARCHAR type as it can then contain any data you want; numbers or text. But character data is amongst the most inefficient data type you can get. If a field is only going to contain numbers, then make it one of the appropriate types (INT, DOUBLE, etc).

Also, wherever possible in your web development code, try to use numeric data types as opposed to characters. One of the most common things a script has to store are flags like whether someone answered yes or no to a question, etc. You could of course store it as 'Y' or 'N' but why not store it as 0 and 1?

The reason this makes a difference is when you have a database, for example, with over 500 000 entries, and are running a SELECT on that field, comparisons are processed a lot faster for numeric data types than character types. Also, if you need to return data to the calling script, numeric data is less memory intensive than character data. In addition, your web development language (PHP, ASP, etc) would also be able to process and perform functions on numeric data better than character data.

I am not trying to convince you never to use character data types. Sometimes it is a necessity, but if you can find ways to reduce the amount of character data processed by your SQL database, the better your server will cope.

2. Normalization

Normalizing a database is really quite a complex process. It is a process that describes a way to design a database structure to avoid repetition of data in your database and can lead to significant performance benefits if employed correctly. However, the entire process of normalisation is a bit beyond the scope of this article as it can fill books on its own, but any developer designing a database should seriously consider becoming knowledgable about normalisation and employing it in their own designs.

For a good tutorial on this process: http://www.keithjbrown.co.uk/vworks/mysql/mysql_p7.php

3. DateTime vs Timestamp fields

This actually relates to 1. a bit. The big difference to bear in mind here is that a field of type DATETIME is actually stored as a series of characters. A field of type TIMESTAMP is actually stored as an integer. So therefore, a more efficient way of storing dates is using the timestamp method. The timestamp has its drawbacks however. For one, you cannot store a date early than 1 January, 1970. Also, timestamps in your script will need recalculating to get to the character format. Because of this recalculation, it may not be better to store as timestamp. It really is a case of testing which format works better for your needs.

4. Use LIMIT where possible

In your queries, if you are doing a SELECT to a database and you only expect a certain number of results, using the LIMIT statement can speed your query up incredibly.

For example, if you have a table of users and you need to run a query to search for one users record, you can use a query like:

SELECT user_name FROM users WHERE user_id = 453;

This query is perfectly valid and will return the right result. But you also know there will only be ONE result. The query above will search the database, find what you want, but then still continue searching after that. It would run a lot faster if you could tell the query that once it has found what you are looking for to stop searching. LIMIT can do this, as this query shows:

SELECT user_name FROM users WHERE user_id = 453 LIMIT 1;

Imagine this scenario. You have a table called logins, that records every login from a user. It currently contains over 2 000 000 records, and you want to find the first time a user logged in. Now bear in mind that because this table inserts data over time, it is already sorted for by date. You could do the following query:

SELECT MIN(login_date) FROM logins WHERE user_id = 4876;

This will return the record you want, but SQL will now have to get all dates for that user, sort them and then return the lowest value to you. Our table is already date sorted simply because of the way it records data for us. So using LIMIT can be more effective:

SELECT login_date FROM logins WHERE user_id = 4876 LIMIT 1;

Because it is sorted, the first one will always be a users first login.

5. Avoid using LIKE

If you have tried to employ 1. above, then hopefully you will be in a scenario where you do not need to use LIKE all that much. LIKE is one of the most inefficient ways of searching a table. LIKE performs a text comparison search in a field and with no wildcards is as efficient as a direct comparison; i.e. WHERE name = 'Jane' is equivalent to WHERE name LIKE 'Jane'. It is when you start introducing the wildcard characters like '%' that things get really hairy.

If you do have to use LIKE, then at least try and make efficient use of the wildcards. These are '_' (underscore) and '%'. Let me explain all this with a real world example.

In a project I was involved in, we had a SQL database storing logs generated automatically from a mail server. Unfortunately, the mail server pretty much just dumped a very long string of text data into a field that contained the data we wanted. A script had to be written to find all logs that referred to a login by a user into the POP server. The only way we could do this was to search every record for a string in the msg field that had the text "User logged in" in it. The first query developed was something like this:

SELECT msg FROM logs WHERE msg LIKE '%User logged in%';

This query took on average of about 35 minutes to process. Obviously not an ideal situation. The way the LIKE worked here was that it had to parse through every single portion of each and every record in the msg field looking for text that matched "User logged in" anywhere in the text. We were able to determine eventually that the text "User logged in" occured at the end of that text in the msg field and so we altered the query:

SELECT msg FROM logs WHERE msg LIKE '%User logged in';

The '%' at the end was removed as we do not want to worry about text after because there is none. The query now only compares text to our string in the msg field at the end of the field and no longer parses through the entire piece of text stored in msg. The query now ran in under 2 minutes. (This was actually still too long, but how we optimised from there is a little beyond the scope of this article.)

Hopefully with all these elements put into practice on your next web development project, you can have a database that runs quickly, efficiently, uses as little resources as possible and wont grind to a halt when the load suddenly increases.

AJAX is a cross-platform technique that can be use on different operating system and web application based on JavaScript and DOM. It is a powerful approach of web application technique using client-side scripting to exchange data with the web server. This means that with AJAX, web pages increases interactivity and faster responsiveness of user interface by having an independent communication with the server. Gone are the traditional ways of web browsing whereby a new page communicates with each user's request. This creates dynamic web application user interface that renders effective usability of every desktop applications. AJAX primary purpose is to increase the web page's interactivity, speed, functionality, and usability.

Ajax, by definition, is not technology. In fact, it is an application of several technologies. Ajax incorporates several existing web application like XHTML and CSS for standard-based presentation; the Document Object Model for dynamic display and interaction; XML and XSLT for data interchange between the server and the client; the XMLHttpRequest to exchange asynchronous data with the web server; and the use of JavaScript as the core code for running AJAX application.

To understand AJAX, first we must know how the traditional web application works. The classic web interface trigger an HTTP request back to web server. The server then process and retrieve data before returning an HTML page to the users. This process as a model for hypertext medium makes technical sense. But as web application evolves this process does not make the user interface more interactive and practical.

AJAX, on the other hand, eliminates this problem. AJAX speed up the loading of any web application with the use of intermediary between the user and the server called AJAX engine. This adding of another layer application of eliminates the start-stop-start-stop nature on the web. The browser loads an AJAX engine at the start of session.

The AJAX engine allows the user interface and the application to interchange data asynchronously-independent of the communication to the server. So the interaction between the user and the web never slows down, no point of waiting for the server to do something.

AJAX is a powerful technique that grows exceedingly as web application. That is, AJAX is now part of the guiding principle as web 2.0 flourishes and become a practical reality. With the power of AJAX, many of the business and marketing web site are integrated with AJAX application server platform now. Most of the major products of Google such as Gmail, Google Maps, and Google Suggest are employing AJAX application. Other web services like the photo-sharing application Flickr, Amazon's A9.com, and the new Yahoo! maps depends on AJAX. The application of AJAX comes from simple function to the most complex program like Google Maps.