A database is a software-based container structured to collect and store information so it can be retrieved, added to, updated or removed in an automatic fashion. Database programs are software applications designed for users to make databases and create all the programming necessary to fill them or delete them as needed. The structure of a database is the table, which consists of rows and columns of information. The columns identify the data (attributes) in the table, and the rows are the records of information. Tables look just like a spreadsheet, but tables can be manipulated and updated in a manner that spreadsheets cannot, which makes a database a very valuable tool.
A database structure is defined by its database model. The model used most is the relational database model. The tables in this model must relate, or link, to each other with each table holding specific information or attributes (columns) about each record (row). For example, a veterinarian may have a table called "Patients"--with columns titled "Patient's name," "Patient type" and "ID number"--and a second table called "Patient's Owner"--with the columns titled "ID number," "Owner name," "Owner address" and "Owner phone number." The first table links to the second table by the ID number. The relationship of the ID number is how a report or query request finds records that belong together and can return an accurate response.
Database design is an art based on business requirements. The business requirements must be understood before an accurate and useful database can be designed. Business requirements can also be called business processes. The tables should hold no more than one set or module of information. For instance, in the previous example, the “Patient” table should not hold information about the patients' visits. Instead, a separate table would hold a visit ID number and the date and the time of the visit along, with the patient ID number to link it to the patient. A fourth table titled “Billing” would be created to identify the payment amount, payment type and the visit ID being paid for along with the patient ID. Billing and visits are business processes.
Entering records fills a database with data. Once the database is structured correctly, an interface is built. This interface is placed between the tables and the user. It gives the user a different view of the database. Using our veterinarian example, an interface might give the user a “New User” entry page. On this page, the user can enter the pet's name and type, the owner's information and the date and type of the first visit. All of this information is contained in three different tables located behind the interface, but the user only needs to interact with the entry page (a single form) while the data drops into the correct tables. This is achieved by linking the tables via simple programming.