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.

As you know we are all fond of the easy things in life. We all like the path of least resistance. The easier we can find our way the better for us. The more complicated something appears the less we understand it and as consequence the less we like it.

With this in mind we need to approach the building of a website in a way that will avoid all of the above. Your website will need to be laid out in a way that understands the visitor's needs and addresses them clearly and concisely.

The question then becomes how to do this? When considering what subject to build your site around you will need to start your research on the forums relative to the topics of choice. For example if your passion relates to golf then you will need to visit forums where this subject is discussed.

Here you will need to look at what questions are being asked and where the people posting to this forum are having difficulty. Then you will need to get engaged and try and help. Here is how you could do this. Create a signature that links back to a free blog that asks the question "what is the biggest problem you face when it comes to golf"

On your free blog you could ask other questions. Your blog then can have a form where people can submit their questions. Of course you would need to offer them something to do this that will help their game and of course you will need to offer it for free.

Based on this you will be gathering actionable intelligence relative to your target market. With this information you can then build a website that addresses these concerns and provides a product that you are either affiliated with or that you have created yourself.

Now that you have this information you can build a real website that can generate a real income in multiple ways. You will want to build a site that is structured properly for the search engines and one which is easy to navigate for your visitors.

To conclude if you lay the groundwork properly then the rest will fall into place.

Functions are used to perform a well defined task that is normally repeated at various places within a web site, web application, or other software application. The function sometimes needs certain information before performing its task, and sometimes returns a value to the calling page or program.

An example of how to use a simple function in PHP:

 function showMessage() {
echo "{$_SESSION["message"]}"; }

The above example shows a very simple function that displays the contents of a session variable called 'message'. The idea being that while a user is using a web site, etc, various messages are generated and stored in the 'message' session variable. Whenever the showMessage function is called, the contents of the session variable are displayed. So, for example, when the user logs on, you could display a message saying that they have done so. Likewise, when they log off, a different message could be displayed.

Calling a function

To call the showMessage function, you would just need to include the line:

showMessage()

in the web page (wrapped in php tags to distinguish it from normall HTML).

Passing values to a function

Often, a function requires one or more input values in order to perform its task. For example, take the following example that takes two numbers as input, and adds them together. The result is then returned to the calling web page or program.

function addNumbers($number1,$number2) {
$answer = $number1 + $number2;
return $answer; }

In the calling program we would have something similar to the following:

$number1 = "5";
$number2 = "6";
$sumOfNumbers = addNumbers($number1,$number2);
echo "$sumOfNumbers";

Obviously, in a real program you would not have the numbers hardcoded like this, but they would be obtained from user input or by some other means. Notice also that although the name of the returned variable is $answer, the calling program makes no reference to that. We could, if we wanted to, change the calling program to:

$answer = addNumbers($number1,$number2);
echo "$answer";

which might make things slightly easier to understand.