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| Three Tier Structure |
| The Calsoft application may seem very straightforward to the everyday user; however, what the user sees is only a small portion of the application. Calsoft can be best explained as being composed of three layers. |
| The first or bottom layer is the database layer. In this application, relational database is used to store information that will be needed later. The data is stored in tables, with values in their corresponding fields in the table. |
| Information is gathered from the database via structured query language (SQL). The SQL query language is interpreted by the database, MySQL. The database performs tasks in response to commands entered and can be very useful to the software because of the manipulation of stored information. From a string of commands, MySQL can select any information of a specified variety or that meets a series of special conditions. MySQL can also insert entries of data, remove entries, or update existing entries based on specific conditions. |
| The second or middle layer is the dynamic scripting layer. Dynamic scripting on this website is done via PHP, a language used to write dynamic web pages that are interpreted by the server. PHP is a powerful tool because variables can be declared in the code that can be filled in by the user and translated to markup language that browsers can display. This is used to make dynamic or "custom" web pages based on the specific user or data she has entered. |
| Markup language, most commonly HTML, is translated into text and images by the browser at the display layer. This website happens to use two markup languages: HTML and CSS. HTML is used to display text and images in a specific manner determined by tags, each of which has a certain function. |
| CSS stands for "cascading style sheet." It is used to preset details or styles to be associated with certain tags which specify text font, size, color, and other details. This can be useful to programmers if they are going to be repeating a certain style or sets of styles throughout their website, because they will not have to specify the individual details of the style each time they call another page. |