Database
 

[B]One of the technology terms that most people have become accustomed to hearing either at work or while surfing the internet is the database. The database used to be an extremely technical term, however with the rise of computer systems and information technology throughout our culture, the database has become a household term.


The definition of a database is a structured collection of records or data that is stored in a computer system. In order for a database to be truly functional, it must not only store large amounts of records well, but be accessed easily. In addition, new information and changes should also be fairly easy to input. In order to have a highly efficient database system, you need to incorporate a program that
manages the queries and information stored on the system. This is usually referred to as DBMS or a Database Management System. Besides these features, all databases that are created should be built with high data integrity and the ability to recover data if hardware fails.

[SIZE="4"][COLOR="Red"]Types of Databases[/COLOR][/SIZE]
There are several common types of databases; each type of database has its own data model (how the data is structured). They include; Flat Model, Hierarchical Model, Relational Model and Network Model.

[COLOR="red"][SIZE="4"]The Flat Model Database[/SIZE][/COLOR]

In a flat model database, there is a two dimensional (flat structure) array of data. For instance, there is one column of information and within this column it is assumed that each data item will be related to the other. For instance, a flat model database includes only zip codes. Within the database, there will only be one column and each new row within that one column will be a new zip code.

[COLOR="red"][SIZE="4"]The Hierarchical Model Database[/SIZE][/COLOR]
The hierarchical model database resembles a tree like structure, such as how Microsoft Windows organizes folders and files. In a hierarchical model database, each upward link is nested in order to keep data organized in a particular order on a same level list. For instance, a hierarchal database of sales, may list each days sales as a separate file. Within this nested file are all of the sales (same types of data) for the day.

[COLOR="red"][SIZE="4"]The Network Model[/SIZE][/COLOR]

In a network model, the defining feature is that a record is stored with a link to other records - in effect networked. These networks (or sometimes referred to as pointers) can be a variety of different types of information such as node numbers or even a disk address
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Accessing Information Using a Database[/COLOR][/SIZE]
While storing data is a great feature of databases, for many database users the most important feature is quick and simple retrieval of information. In a relational database, it is extremely easy to pull up information regarding an employee, but relational databases also add the power of running queries. Queries are requests to pull specific types of information and either show them in their natural state or create a report using the data. For instance, if you had a database of employees and it included tables such as salary and job description, you can easily run a query of which jobs pay over a certain amount. No matter what kind of information you store on your database, queries can be created using SQL to help answer important questions.

[SIZE="4"][COLOR="red"]Storing a Database[/COLOR][/SIZE]
Databases can be very small (less than 1 MB) or extremely large and complicated (terabytes as in many government databases), however all databases are usually stored and located on hard disk or other types of storage devices and are accessed via computer. Large databases may require separate servers and

locations, however many small databases can fit easily as files located on your computer's hard drive.
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Securing a Database[/SIZE][/COLOR]
Obviously, many databases store confidential and important information that should not be easily accessed by just anyone. Many databases require passwords and other security features in order to access the information. While some databases can be accessed via the internet through a network, other databases are closed systems and can only be accessed on site.


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