The Relational Model
The relational model is the most popular type of database and an extremely powerful tool, not only to store information, but to access it as well. Relational databases are organized as tables. The beauty of a table is that the information can be accessed or added without reorganizing the tables. A table can have many records and each record can have many fields. Tables are sometimes called a relation. For instance, a company can have a database called customer orders. Within this database are several different tables or relations all relating to customer orders. Tables can include customer information (name, address, contact, info, customer number, etc.) and other tables (relations) such as orders that the customer previously bought (this can include item number, item description, payment amount, payment method, etc.). It should be noted that every record (group of fields) in a relational database has its own primary key. A primary key is a unique field that makes it easy to identify a record. Relational databases use a program interface called SQL (Standard Query Language). SQL is currently used on practically all relational databases. Relational databases are extremely easy to customize to fit almost any kind of data storage. Relations can easily be created for items for sale, employees in a company, etc.