Most database management system enacted on RDBMS(Relational Database Management System) base. The keyword is “Relational.” The way how to make relations mostly determines the whole performance.

There are 3 types of relation – 1:1, 1:n and n:m. Let’s take a look for each.

One-to-One(1:1) relation
Although it is rarely used as all 1:1 relations can be expressed as one composite dataset, understanding the concept would help to see the connections more clear. A student and his student ID match is an example. One student has one ID and one ID is possessed by one student.

One-to-Many(1:n) relation
It is the most common relation that most hierarchical structure can be represented with it. For example, suppose that 16 full-time employees are working in a company. Then the company has 16 employees, and each employee belong to one company.

Many-to-Many(n:m) relation
This relation is the most complicated structure among relations so it requires the performance overhead. It traverses N*M times to search for data while One-to-Many relation does it N times. One of good examples is the relation between class and student. Students take many classes and each class has many students.

The key is that, avoid Many-to-Many relation to maximize performance. If it is inevitable, count the number of data records and control it with discussion. The performance is not to be ignored in web service.

Validation of Web Standard (W3C Validation)
The main reason of this phase is that many browser vendors have made their programs so differently. Keeping web standard may help your service shown identically regardless of browser environment. W3C, who enacts the web standard offers a service to validate online. (http://validator.w3.org) Insert your site address and click Check button to conduct validation. If you meet some errors or warnings, you’d better remove them all.

Optimization
Optimization is important to improve the performance of the service. According to the statistics from Amazon.com, 0.1 second speed-up brings 1% revenue increment. There are some issues about the method so you can consider them. Here is a list of optimizing stuffs.

- Locating inline script and stylesheet(CSS) properly.
- Deferred script.
- Gzip compression.
- Seeing how CSS selector operates in browser.
- Optimization of images (GIF, JPEG, PNG, etc)

Security Manners
It is essential to sanitize user’s input. You’ll get a big trouble by hackers who targets at the core information in your site unless missing security managing process. That is, the personal data and information could be divulged or manipulated. The range of security is broad but you can see the following issues primarily.

- XSS (Cross-site script) attack.
- SQL injection.
- Intercepting user session.
- Exploiting vulnerabilities of browser.