Although the information stored in databases may give the organization the ability to do many things that would be otherwise impossible, it is database management systems that make the data available to users and allow them to access and process them so that they can be used in business applications. Database management systems are software programs that allow users to manage the data in a database. Database management systems are designed to increase the accessibility of data and the productivity of the user. To do this, database management systems integrate databases so that users can get the answers to questions they need, reduce data redundancy, enable the sharing of information among multiple users at various locations, and maintain the integrity (a combination of security and reliability) of the database.
Business Information Systems
In the information age, it has become a truism that information is power. If an organization has information about the needs of the marketplace, it can design a better widget and earn a larger market share. If an organization has information about what the competition is doing, it can develop a strategy to meet or exceed their competitors, thereby winning a competitive advantage. If an organization has information about prospective and current customers, it can build relationships with them and influence their perceptions of the organization and its products and services.
Information technology (IT) enables organizations to do these things and more in ways that were not previously possible when data had to be tracked manually. Through the use of computers and communications networks in the creation, storage, and dispersal of data and information, the flow of information and data between people or departments can be facilitated better than ever before. Arguably, however, it is databases (collections of data items used for multiple purposes which are stored on a computer) that give information systems their power. Databases can be used in a wide variety of situations ranging from personal productivity to enterprise-wide applications that are used by multiple users and maintained by IT professionals. The information in databases is managed by software programs called database management systems. These systems are designed to increase the accessibility of data and the productivity of the user.
There are a number of reasons to use databases. First, databases are the sine qua non of information systems because they are where the data used by the system are stored. Unless data are accessible, they cannot be retrieved and used. For example, homeowners often need to hire contractors to do various jobs ranging from painting the shutters to fixing the plumbing. Although some contractors are both honest and professional, others are not. Therefore, many homeowners ask their neighbors for recommendations about who they have used successfully for similar jobs. This information is often stored away on bits or paper or business cards or even entered into an address book. However, when the roof starts leaking and the grand piano is getting wet, it is often difficult to remember where the scrap of paper with the name of the recommended roofer is or even which neighbor recommended the company. Databases help solve this problem by storing all data about a particular subject in one location.
Just knowing where the data are located, however, is insufficient. One must also be able to retrieve them. For example, if Harry Homeowner knows that the roofer's information is in the kitchen junk drawer, he still may have to go through many pieces of paper with various contractors' contact information on them before he finds the information he needs. In addition, Harry may find that the kitchen drawer has information on more than one roofer, so he needs to remember which one was recommended and which one was not. In information technology terms, this process is called retrieving the data. To retrieve data from a database, one needs to query the system. A query is a search question used by a database management system to specify which data are to be retrieved from the database. So, for example, if Harry had a database of contractor information, he could query the system to retrieve all the data on roofing contractors. Unless there only a handful of cards in Harry's kitchen drawer, the process of querying a database is likely to produce the name of the contractor much more quickly than is manually searching through the kitchen drawer. Harry could search the database using a number of different queries, including the contractor's name or specialty (e.g., roofing or roof repair). If, on the other hand, the grand piano in the living room was getting soaked because of leaky plumbing, Harry could just as easily query the database for plumbers and retrieve that information.
Like the rest of life, the information in a database is not static. A-1 Roofers may move and change their address or add a website that Harry may want to include in his database. Or Harry may try A-1 Roofers and find that they have a new employee who does not do a good job or that they have changed their price structure and their services are no longer affordable. As a result, Harry may want to include a notation with their other information to specify that he does not want "Mike" to come out or that A-1 is overpriced. To do this, Harry needs to edit the database -- that is, he needs to add, delete, or change the information that is stored in the database. Not only can the specific data of a record be edited, it can also be reclassified so that the database can be organized in a different manner. For example, A-1 Roofing may decide to expand the services that it offers and change its name to A-1 Contracting. Harry could edit its record in the database to reflect the name change and also add the category "drywall repair" to the record. That way, when Harry decides that he does not want to repair the damaged walls that resulted from the leak (whether it is a plumbing or roofing problem) himself, when he queries the database for drywall repair, A-1 Contracting will be retrieved as part of the search.
In addition, database management systems are used to distribute data and information. For example, Harry may only want to view a list of roofing contractors and their phone numbers, or he may want to view details of their contact information and any comments he has input into the system about them. Although Harry may just want this information to be displayed on the computer screen for his purposes, if he wants to pass on the information to a neighbor who also has a leaky roof, he way want to print out the information in any one of a number of different formats. In a more complex example, if Harry were the marketing manager of a large roofing supply company, he could use a database to generate form letters and mailing labels so that he could advertise the company's products and services to hundreds or even thousands of contractors. He could also transmit information about local roofing companies to corporate headquarters using a communications network.
Special Purpose Databases
In addition to general purpose database systems that are managed with generic database management system software that can be applied to virtually any database, there are also special purpose databases that are designed for a specific use. Directories list information by category, such as a telephone directory that lists names of individuals or organizations and contact information for where they can be located. Personal information managers are database management system that allows users to manage data to organize their personal activities. For example, personal information managers may contain a contact list of names, addresses, phone numbers, e-mail addresses, and other details for business and personal contacts. Database management software can retrieve the contact...
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